time strike that saw Rafael Benitez's side sneak into the Europa League last 16 at the expense of Sparta Prague.
Just nine months on from winning the Champions League, the west Londoners only just managed to overcome the side third in the Czech top flight at Stamford Bridge.
Hazard grabbed the all-important goal to avoid extra time and, more pertinently, the potential of an embarrassing Europa League exit on home turf.
Unstoppable: Hazard's rocket prevented the match from going into extra time at Stamford Bridge
MATCH FACTS
Chelsea: Cech, Cahill, Terry, Azpilicueta, Bertrand, Ramires, Mata, Oscar (Hazard 67), Mikel, Moses, Torres
Subs not used: Turnbull, Cole, David Luiz, Ferreira, Marin, Benayoun
Booked: Bertrand
Goal: Hazard 90
Sparta Prague: Vaclik, Svejdik, Hybs, Zapotocny, Matejovsky, Krejci, Mario Holek, Vacha, Prikryl, Lafata (Leonard Kweuke 82), Kadlec (Bednar 90)
Subs not used: Cech, Vidlicka, Polom, Janos, Pamic
Booked: Lafata, Hybs. Matejovsky, Prikryl
Goal: Lafata 17
Referee: Aleksandar Stavrev (Macedonia)
Rafael Benitez's side came into the match boasting a 1-0 lead from last week's first leg in the Czech Republic, leading the Spaniard to rest Frank Lampard and Branislav Ivanovic ahead of Sunday's trip to Manchester City.
Any talk of complacency had been downplayed in the build-up but after just 17 minutes the reigning European champions were behind, with David Lafata firing home from close range.
Things could have been different had Fernando Torres found the net with one of the many chances he wasted in the first half, while Juan Mata was denied by a fine save by Tomas Vaclik.
The Sparta Prague goalkeeper's heroics kept Chelsea at bay after the break, having seen Ramires hit the post two minutes into the second period.
The visitors, though, were not being outplayed and looked set to take the tie to extra time - but substitute Hazard had other ideas, lashing home a stoppage-time leveller to put the Blues through on aggregate.
One up: David Lafata (back) celebrates after levelling the tie up
Agony and ecstasy: Lafata (centre) wheels away as Gary Cahill (left) expresses his anger
Frustation: Petr Cech was disappointed after conceding against his old club
It was a performance that belied Chelsea's confident start to the game.
Victor Moses, one of four changes to the starting line-up in Prague, took just four minutes to create the night's first chance, although his pull-back was directed wide by Torres.
Oscar then saw a hopeful long-range effort deflect behind in a strong Chelsea start, before Torres again came close. This time the £50million striker hooked an excellent Juan Mata cross onto the roof of the net.
Torres was getting a lot of the early action and also headed over, with Vaclav Kadlec producing Sparta's only real threat.
The visitors, though, clearly felt the hosts were susceptible on the break and netted the opener against the run of play.
Kadlec gathered a quick free-kick in the box and jinked past Gary Cahill before laying off for Lafata to rifle home from close range, much to the delight of the 3,000 visiting fans.
In the mix: John Terry tackles Sparta Prague's Vaclav Kadle at Stamford Bridge
Making do: Frank Lampard watched the match from the stands after being rested
Work to do: Chelsea manager Rafael Benitez substitutes Oscar during the second half
Oscar saw a strike blocked as he attempted to immediately hush the raucous visiting support, before Mata poorly curled over a free-kick.
It was the visitors, though, who were in the driving seat, with Petr Cech forced to save a low strike from the unmarked Tomas Prikry.
Marek Matejovsky volleyed over from the resulting corner and, after a break in play for referee Aleksandar Stavrev to receive treatment, Lafata twice tried - and failed with - long-range efforts.
Chelsea looked understandably shell-shocked but ended they first half on top, with only Vaclik's acrobatics denying them a leveller.
Mata met a Ramires ball over the top with a tremendous touch only to see his goalbound strike pushed over by the Sparta goalkeeper.
Nice try: Fernando Torres watches his attempt at goal saved
Torres headed wide unmarked late on, with half-time met by boos from the Chelsea faithful.
Their team returned after the break rejuvenated, with Ramires taking just two minutes to rattle the Sparta goal frame.
Their team returned after the break rejuvenated, with Ramires taking just two minutes to rattle the Sparta goal frame.
The Brazilian hit the near post after latching onto a ball from countryman Oscar, before Moses struck wide from 25 yards.
Torres was the next to threaten but, like so many times already this evening, he could not find the net. The Spaniard raced beyond the Sparta backline but his dinked effort was thwarted by Vaclik.
Supportive: Sparta Prague fans fill up the away end before the match
The Sparta Prague goalkeeper was proving the scourge of Chelsea, with John Terry next to be denied when he tried a flick over his shoulder.
Vaclik palmed that away and Sparta almost capitalised, with captain Matejovsky breaking through the middle only to fire just wide of Cech's far post.
Chelsea fans broke into a chorus of 'Jose Mourinho' soon after as current incumbent Benitez replaced Oscar with Hazard - a change met by boos from the home support.
Chelsea upped the ante in the closing 15 minutes in a bid to avoid extra time, with a Hazard free-kick almost sneaking in, before Azpilicueta and Ramires blazed over.
Kadlec twice came close in stoppage time, before the travelling fans' hearts were broken.
Substitute Hazard was the man who did the damage, finding space in the left-hand side of the box to fire home a stoppage-time leveller and put Chelsea through 2-1 on aggregate.A Jamie Carragher error ultimately proved costly as Liverpool were edged out of the Europa League despite a fine comeback against Zenit St Petersburg.
The veteran defender, making his 150th - and now last - European appearance, gifted Zenit's star forward Hulk a goal that gave the Russians a 3-0 aggregate lead early in the second leg of the last-32 tie.
Liverpool responded as top scorer Luis Suarez fired in two free-kicks and Joe Allen struck from close range but Hulk's vital away goal prevented another memorable Anfield fightback.
Gone: Jamie Carragher's error proved decisive as Liverpool went out on away goals
MATCH FACTS
Liverpool: Reina, Johnson, Carragher, Agger, Jose Enrique, Lucas, Allen (Shelvey 59), Downing (Sterling 84), Gerrard, Henderson (Assaidi 59), Suarez.
Subs not used: Gulacsi, Coates, Suso, Wisdom.
Booked: Shelvey.
Goals: Suarez 28, 59, Allen 43.
Zenit St Petersburg: Malafeev, Aniukov, Luis Neto, Lombaerts (Criscito 46), Hubocan, Witsel, Denisov, Shirokov, Danny (Faitzulin 46), Hulk, Semak (Rodic 84).
Subs not used: Zhevnov, Bruno Alves, Bukharov, Kerzhakov.
Booked: Denisov.
Goals: Hulk 19.
Att: 43,026
Referee: Bjorn Kuipers (Holland)
Liverpool's history is littered with stirring tales of European recoveries and the crowd longed for another to breathe new life into an inconsistent season.
The hosts went into the game with plenty of noise behind them and they looked determined to feed the atmosphere with the goals they required.
Brendan Rodgers' men were positive from the outset with Suarez, once again the main attacking focal point in the absence of the ineligible Daniel Sturridge, looking lively.
Suarez attempted to get behind the defence at every opportunity and almost got in on goal from a Jose Enrique long ball but he could not control.
Jordan Henderson won possession on the left but shot straight at Vyacheslav Malafeev from distance and Steven Gerrard lined up a free-kick only to blaze over.
Yet Zenit had no intention of sitting back on their advantage and there was a warning for Liverpool as Danny broke through and Carragher came across to block his run.
Carragher also made another timely interception but the Liverpool veteran had nowhere to hide after the 19th-minute blunder which gifted Zenit the opener.
Error: Hulk pounced on Carragher's mistake to score the crucial away goal for Zenit
The 35-year-old was under little pressure when he miscontrolled a speculative pass into the Liverpool half but Hulk quickly seized on the ball.
The £32million Brazilian, who scored in the first leg, raced through on goal and fired past Jose Reina with conviction.
The away goal left Liverpool needing to score four times to salvage the tie and they needed a quick response.
Mountain: Hulk's goal meant Liverpool needed four goals to progress to the last 16
They got it as Daniel Agger burst forward from deep and was felled on the edge of the area by Nicolas Lombaerts.
Zenit sensed the danger and their best to delay the free-kick. Referee Bjorn Kuipers eventually tired of their capers and booked Igor Denisov and Suarez made them pay further by blasting the set-piece through the wall and into the net.
The crowd were reignited and Gerrard won another free-kick in dangerous territory moments later but Aleksandr Anyukov headed the captain's set-piece behind.
Equaliser: Suarez smashed a free-kick through the Zenit wall to level the score at 1-1
Hearts were in mouths when Reina miskicked with Hulk again threatening but the goalkeeper recovered and Liverpool tried to build again.
There were further scares when Danny chested down a Hulk cross and volleyed narrowly wide and Anyukov also hit the side-netting but the Reds grabbed another before the break.
Enrique found space down the left and exchanged passes with Henderson before crossing from the byline for Allen.
Hope: Joe Allen scored Liverpool's second goal from close range just before half-time
Allen's initial header was parried by Malafeev but the Wales midfielder followed up to hook home.
Liverpool carried the momentum into the second half and had a strong appeal for a penalty turned down when Tomas Hubocan appeared to handle after Suarez won a header.
Suarez played on and blasted narrowly wide but Liverpool made their feelings clear to Kuipers soon enough.
Comeback: Liverpool still needed two goals after half-time if they were to win the tie
It did not dent their enthusiasm and Zenit found it increasingly difficult to hold the Merseysiders back.
The next breakthrough came just before the hour after Suarez was fouled by Roman Shirokov outside the box.
Suarez and Gerrard stood behind the free-kick but it was the Uruguayan who again stepped up, curling an inch-perfect shot into the top corner.
Beauty: Suarez curled in a free-kick in front of the Kop to put Liverpool 3-1 ahead on the night
That increased the noise level yet further but there was another warning for Liverpool when Hulk flashed a free-kick wide after substitute Jonjo Shelvey was booked for a crude challenge.
Another substitute, Oussama Assaidi, made a more positive contribution before being pulled back on the edge of the area.
Suarez fancied a hat-trick of free-kicks but his effort was beaten away by Malafeev.
Gerrard produced an acrobatic effort to get a shot on target from an awkward bouncing ball but Malafeev, who had pushed the ball in his direction, recovered to save again.
At the other end Reina saved well from Hulk and Liverpool attacked again with Shelvey firing wide.
Liverpool kept up the pressure until the end, with Reina going forward for a late corner, but it was not to be and Zenit will now face Swiss side Basle in the next round.
Dejection: Suarez shows his disappointment as Liverpool went out of the Europa League
Good effort: Brendan Rodgers shakes hands with defender Daniel Agger
