Branislav Ivanovic has admitted that Shane Long proved a 'nightmare' to play against during Serbia's 1-0 World Cup qualifier win against Republic of Ireland on Tuesday night.
The former Chelsea defender helped the visitors keep a clean sheet and leave Dublin with a crucial victory at the top of Group D.
But he stressed after the game that the win was a difficult one due to the threat of Ireland's attacking players.
"I know how Premier League football works, but this was the toughest I have ever played against," Ivanovic said, quoted by Sky Sports.
"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."
Ivanovic's defensive partner Nikola Maksimovic was sent off in the 68th minute, but Serbia remained resolute.
"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," Ivanovic added. "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."