rigours of playing at high altitude.
The forward, who has scored 51 goals for Barcelona this season and second only to Diego Maradona in Argentina's all-time scoring list, was reportedly sick on the pitch during half-time as he struggled in the thin air of La Paz, nearly 4,000 metres above sea level.
Team-mate Angel Di Maria had to be given oxygen on the pitch during the 1-1 draw.Bolivia went ahead in the 25th minute when striker Marcelo Martins rose above defender Hugo Campagnaro to head Alejandro Chumacero's right-wing cross past Sergio Romero.
Argentina, who had a good chance for striker Rodrigo Palacio saved by goalkeeper Sergio Galarza with his feet, equalised one minute before halftime.
Messi beat two defenders and fed left back Clemente Rodriguez whose centre was headed home by midfielder Ever Banega past the diving Galarza.
But they might have won had Messi made the most of a late chance.
Messi stole the ball from a defender and came face to face with Sergio Galarza but a moment's hesitation cost him dear and allowed the goalkeeper to block his shot.That preserved Bolivia's record as the only South American team to have denied the little ace a goal.
'That's another point we have added and (this result) strengthens the squad (but) we deserved all three,' said Argentina coach Alejandro Sabella.
'Obviously we have good chances (of qualifying), we've gone from moderate optimism to greater optimism,' he said after taking four points in four days following Friday's 3-0 win over Venezuela in Buenos Aires.
Messi was feted by the Bolivian president Evo Morales after Tuesday night's World Cup qualifier for his 'human and sporting qualities'.
