Skipper Branislav Ivanovic saluted Serbia's bravery after they survived a "nightmare" challenge in Dublin to edge their way to the brink of World Cup qualification.
Aleksandar Kolarov's goal secured a 1-0 win over Group D rivals the Republic of Ireland at the Aviva Stadium on Tuesday to leave the Serbs four points clear of second-placed Wales and a further point better off than Martin O'Neill's men with just two games to play.
However, they found themselves facing an Irish onslaught, particularly after defender Nikola Maksimovic's 68th-minute dismissal, leaving former Chelsea defender Ivanovic and his defensive colleagues battling to keep the likes of Shane Long and Jonathan Walters at bay.
Ivanovic said: "I know how Premier League football works, but this was the toughest I have ever played against.
"It was a duel all around the pitch, definitely the toughest game we have played so far in the group. I am very proud we showed the courage to come out with the three points.
"We are naturally physical and we have our talents and some of those don't compare with the Irish players and the way they play, especially in the way they attack, but we accept this as natural.
"Both Shane Long and Jon Walters were a nightmare, an absolute handful to mark. I had to stay completely focused on both of them at all times."
Serbia travel to Austria and host Georgia next month, when one win would guarantee automatic qualification and a trip to Russia next summer.
That scenario might have been very different had they buckled in the wake of Maksimovic's premature departure.
Ivanovic said: "I didn't see the sending off incident properly, but he was last man back and in that case with a referee it is usually a red. The referee saw it better than us.
"We were definitely a bit panicky and under pressure after that. We were probably not very composed.
"But this was our dream to go to a World Cup and the players fought for everything. We knew if we lost this game, we would be in real trouble in the group.
"This has been a massive, huge step and we are really happy about the result."