Argentina cruise to 3-0 win over Bolivia
Angel Di Maria took over as captain in Messi's absence and shone, providing two assists before halftime.
"It's two games in, we knew it was important to get six points for what's to come," Di Maria told Argentine broadcaster TyC Sports.
"To be handed the captain's armband by the best player in the world is unbelievable, I'm very proud."
Chelsea's Enzo Fernandez made it 1-0 after half an hour when he met Di Maria's cross with a close-range finish to score his third international goal.
"I'm a bit choked, the altitude feels a lot, but I adapted well," Fernandez said after his first match in La Paz, the world's highest capital city at 3625 metres above sea level.
"The game is like that, it's hard to catch my breath but I felt very good."
Bolivia were dealt another blow five minutes later as they were reduced to 10 men after Roberto Fernandez was given a red card for an ugly tackle on Cristian Romero.
Nicolas Tagliafico doubled the lead and scored his first goal for World Cup holders Argentina with a header from a Di Maria free kick in the 42nd minute, before Nicolas Gonzalez's powerful strike sealed the win in the 83rd.
Elsewhere in the second round of CONMEBOL qualifiers, Uruguay play Ecuador, Venezuela host Paraguay, Colombia face Chile, and Brazil visit Peru later on Tuesday.