London - Didier Drogba scored with six minutes left on Saturday to give Chelsea a 2-1 win over Arsenal and a place in next month's FA Cup final.
Both teams had already been hampered by shaky goalkeeping when Arsenal's Lukasz Fabianski rushed out of his area to get the ball, but was beaten by Drogba.
The Ivory Coast striker scored easily into an empty net at Wembley to put the Blues into their second final in three years.
Fabianski, who was playing instead of injured first-choice keeper Manuel Almunia, had been lucky not to concede a goal from a similar error in the first half and was partly at fault for Florent Malouda's 33rd-minute equaliser.
Manchester United and Everton will meet in the second semi-final on Sunday to decide which team meets Chelsea in the May 30 final.
But Arsenal had dominated much of the opening half hour and led when Theo Walcott volleyed in a cross past goalkeeper Petr Cech.
Malouda then equalised with a low shot to the near post, with Fabianski positioned too far to the other side.
The tempo increased later as both teams searched for a winning goal and the Gunners were lucky not to be reduced to 10 men for the last 20 minutes. Midfielder Denilson got a yellow card for pushing the referee when unhappy with a decision.
And Drogba then scored to give Chelsea their first FA Cup win over Arsenal since 1947.