Colombia heaped misery on Lionel Messi and Argentina with a 2-0 victory in their Copa America opener on Saturday.
Runners-up in 2015 and 2016, Messi's Argentina were looking to banish their past demons in pursuit of a first major international title since 1993.
However, Argentina were upstaged by Colombia, who made a winning start in Group B thanks to Roger Martinez's 71st-minute stunner and Duvan Zapata's late sealer.
As Argentina pressed and probed, first-half substitute Martinez sent a thunderous strike past Franco Armani in Salvador and Zapata made sure of the win during the closing stages.
Argentina came into the tournament off a 5-1 rout of Nicaragua and with the most Copa victories in history (119) but the South American giants did not look like winning against Colombia.
Martinez – a replacement for Luis Muriel in the 14th minute – linked up with Radamel Falcao but his shot deflected just wide of the post as Colombia appeared the more likely to strike first.
Overall, it was a forgettable opening 45 minutes, which did not see a single shot on target from either team, with Messi subdued.
It was more of the same in the second half, though Colombia goalkeeper David Ospina was finally called into action after a vicious volley from Leandro Paredes approaching the hour mark.
The match did come to life moments later when Juan Cuadrado's tackle on Messi threatened to spark a melee as Argentina players rushed in to confront the Colombia winger.
That triggered Argentina, who almost took the lead after Nicolas Otamendi's powerful header forced Ospina into a low diving save, while Messi was unable to head home the rebound with the goal at his mercy.
But Colombia broke the deadlock with 19 minutes remaining – Martinez collecting the ball on the flank and drifting inside before beating Armani from distance – and fellow substitute Zapata doubled the lead four minutes from the end courtesy of an emphatic close-range finish.
What does it mean? Long road ahead for Scaloni
In the build-up to the match, head coach Lionel Scaloni joked he would retire if Argentina win the Copa America. Scaloni does not appear any closer to retirement based on Saturday's result and performance. After last year's World Cup last-16 exit and Messi's brief international absence, the South American giants have a lot of work ahead.
Martinez makes himself a hero
When Muriel went down with an injury early in the first half, Carlos Queiroz turned to Martinez. And as Falcao struggled to make an impact on proceedings, 24-year-old America forward Martinez emerged a hero with his first international goal since 2016.
Pressure builds on Messi and Co.
The weight of a nation falls on Messi's shoulders and the captain was helpless to prevent another poor result on the international stage. Still searching for his first senior title with Argentina, Messi was relatively subdued in the team's first game.
Argentina meet Paraguay on Wednesday, while Colombia face guests and 2022 World Cup hosts Qatar.