Tauro was moments away from all but eliminating RSL from the tournament when goalkeeper Vladimir Villareal raced far off his line and crashed into Saborio in the penalty area.
Saborio injured his right shoulder in the collision, but never betrayed the pain he was feeling until after he fired the game-winner past Villareal who guessed correctly and dove to his left in the 93rd minute, but couldn't get enough of the ball to keep it out of the net.
That's when Saborio bent over, wincing in pain and calling for trainers as his teammates began to celebrate their most important victory of the season, in a game that was slow to start but turned into a hectic, back-and-forth affair as full time neared.
"It was one of those games where it was risks, both teams taking risks going forward at the end of the game there," midfielder Ned Grabavoy said. "We were lucky enough to get a PK there at the end and lucky enough on the other end not to give up a goal somewhere."
Without the victory, RSL could have been eliminated from the tournament next week, when CS Herediano plays Tauro at home in Costa Rica.
Instead, it will get the chance to eclipse Herediano for first place in their tournament group and claim its only berth into the knockout rounds, when the teams meet in the group-stage finale at Rio Tinto Stadium on Oct. 23.
Saborio already was assured of being out for that game with a yellow-card suspension, but it's unknown how his injury might affect his available for the important Major League Soccer game against Portland at home on Saturday night.
RSL needs points in league play to avoid slipping into the wild-card playoff game.
The team controlled most of the game against Tauro, despite playing sluggishly and without suspended midfielder and captain Kyle Beckerman. It generated some decent scoring opportunities, but never could convert until those final moments.
"It feels good to have a chance to move on in this tournament," goalkeeper Nick Rimando said.