Argentina's Lionel Messi scores with a penalty kick against Paraguay during their World Cup South American qualifying match on Tuesday in Asuncion.

Lionel Messi converted two penalties as Argentina booked its ticket to the 2014 World Cup finals with a crushing 5-2 away win over Paraguay on Tuesday.

Argentina leads the South American group with 29 points and has two qualifiers remaining next month.

The top four qualify automatically and the group leader can now only be overtaken by Colombia and Chile.

"We knew how difficult it is to qualify and this is our reward for all the good work we've been doing," Messi told Fox Sports.

"It wasn't easy to play with the poor state of the pitch, but the main thing was to go for our qualification," he said after the game at Defensores del Chaco stadium.

Messi, Argentina's captain, put his team ahead in the 12th minute at the same venue where Argentina had lost the equivalent qualifier under Diego Maradona four years ago.

Messi converted from the spot after Sergio Aguero was brought down by goalkeeper Roberto Fernandez.

But Paraguay, which began the match with only the slimmest hopes of reaching the fifth-place playoff berth, conjured up a fine equalizer when striker Jose Nunez deflected a left cross past Sergio Romero from a narrow angle six minutes later.

The visitors soon regained the lead, however, when Aguero tallied in the 32nd minute.

With his back to the goal, Messi chested a ball into Aguero's path and the striker nudged it forward before slamming a low left-footed shot inside the base of the far post.

Winger Angel di Maria increased Argentina's lead five minutes into the second half, running onto a through ball from playmaker Fernando Gago and beating Fernandez with a hard, low shot.

Messi's second penalty kick goal came after he was brought down took his tally as joint top scorer in the qualifiers to 10, equal with Uruguay's Luis Suarez and one ahead of suspended Argentina teammate Gonzalo Higuain.

It also took Messi's international tally to 37 in 83 matches, eclipsing Hernan Crespo and vaulting him into second place behind Gabriel Batisuta's 56 in 78.

Paraguay captain Roque Santa Cruz pulled one back in the 85th minute before substitute Maxi Rodriguez, looking to go to a third World Cup tournament with Argentina, rounded off the scoring in the final minute, converting a crafy pass from di Maria.