The drama unfolded just before half-time during Sporting CP's game away against Portimonense, when Sporting’s former Anfield defender Coates had to act quick to come to the aid of his goalkeeper Romain Salin.
The Liverpool Echo report that Salin was left unconscious on the turf after he collided with the goal post just before half time, when trying to prevent his side from conceding their second goal from striker
Seeing that his keeper was in real trouble, the defender acted fast to put his fingers inside Salin’s mouth to ensure he wouldn’t swallow his tongue, making sure his airway didn't become blocked.
Coates then frantically pleaded for the club’s medical staff to hurry onto the field to the aid of his stricken team mate by which time help quickly arrived in numbers.
They initially treated Salin on the field before he was subbed off and taken straight to hospital for further treatment.
While the former Premier League defender's actions had many hailing him as the hero of the day, he was unable to stop his side from slumping to a surprise 4-2 defeat.
Coates, who struggled to really make an impression during his three years at Liverpool, even scored in the 88th minute to bring the score back to 3-2, only for Portimonense to put the game beyond doubt with a fourth and decisive goal later on.
It may not have been the result Coates and his side wanted, but if it wasn't for his quick thinking it could have been a much more severe outcome for Salin.