He's playing in some of the biggest games in world football six weeks out from a World Cup but Mark Schwarzer has no regrets over his international retirement.

He missed a chance to become only the second Australian behind Harry Kewell to play in a Champions League final as Chelsea fell 3-1 to Atletico Madrid in Wednesday's semi-final second leg.

The veteran goalkeeper admitted the defeat at Stamford Bridge was hard to take but he and Chelsea still have plenty to play for as they battle for the Premier League title over the last two rounds.

The 41-year-old, Australia's most capped international, called time on his Socceroos career late last year despite it appearing likely he would find a spot in Ange Postecoglou's squad for Brazil.

An injury to first-choice gloveman Petr Cech last week thrust Schwarzer into some of the biggest games of his career - and what would seem an ideal World Cup preparation - but it hasn't prompted a change of heart.

"I've been loving the position I've been in over the last few weeks and have loved the opportunity to come and play at a club like Chelsea," Schwarzer said after Wednesday's loss.

"But the fact that over the past two weeks things have changed and I'm playing, doesn't change anything [from a Socceroos perspective].

"I made a decision and I think I made the right decision at the right time."

After a brilliant performance in Chelsea's 2-0 win away to leaders Liverpool on Sunday, Schwarzer had a much tougher night against Atletico Madrid.

Despite taking a 1-0 lead through Fernando Torres, Chelsea were outclassed by their opponents as Adrian Lopez, Diego Costa and Arda Turan put the ball past Schwarzer. AAP