The League One Bees were just seven minutes away from producing an enormous upset when Fernando Torres levelled at Griffin Park after Blues midfielder Oscar had scored either side of Marcello Trotta's opener and Harry Forrester's penalty.
Chelsea may have even won if Harlee Dean had been called for handball in injury-time but thankfully for Rosler, the football gods were smiling on Brentford who produced a quality performance against the cup holders.
"There is a football god up there and he is on our side."
Rosler added: "They (Chelsea) had a lot of play but didn't create clear-cut chances. We defended very well and worked very well against the ball.
"And to be five minutes before the end and leading 2-1, I'm slightly disappointed that we didn't win the game.
"But, overall, my players did fantastically. They earned the right to play at Stamford Bridge.
"It will be a great day for our supporters again, for our players and, financially, it will help enormously.
"Also, congratulations to my players for what they did today individually and collectively. That was top drawer."