Weah, who plays for French champions Lille, was drafted into the US starting line-up shortly before kick-off after D.C. United’s Chris Arriola suffered an injury in the warm-up.
The 21-year-old son of Liberian football icon George Weah was instrumental in the winning US goal, picking up a pass from Barcelona wingback Sergino Dest and rifling a shot towards Costa Rica goalkeeper Leonel Moreira’s near-post.
Weah’s effort cannoned off the woodwork and ricocheted off Moreira and into the net for an own goal by the Costa Rica goalkeeper on 66 minutes.
It completed a well-earned comeback for US coach Gregg Berhalter’s young side, who recovered after falling behind to a Costa Rica goal inside the first minute from Keysher Fuller before Dest’s 25th-minute equaliser.
The win in Columbus, Ohio, put the USA on top of the eight-team CONCACAF qualifying standings with 11 points from six games, although Mexico could reclaim top spot with a point or more against El Salvador later Wednesday.
“The team dug in and stuck together and I was really happy with the performance after conceding the first minute goal,” US captain Tyler Adams said.
The US had suffered an upset 1-0 away defeat to Panama on Sunday, when Berhalter was criticised for making seven changes from the team that beat Jamaica last week.
Against Costa Rica on Wednesday, Berhalter returned to the nucleus of the team that had brushed aside Jamaica, making 10 changes, and his team looked a more threatening and dynamic unit as a result.