Michael Ballack [ Images ] scored in the 19th minute of extra time to give Chelsea [ Images ] a 2-1 FA Cup semi-final victory over Blackburn Rovers at Old Trafford on Sunday and set up a Wembley showdown with Manchester United [ Images ].

Chelsea were on top for the first half and deserved to lead through Frank Lampard's [ Images ] well-worked goal in the 17th minute.

Blackburn, beaten three times previously by the Londoners this season, were far better after the break and levelled when Jason Roberts cleverly turned in a Morten Gamst Pedersen free kick in the 63rd minute.

Both sides had good chances to win it in normal time before German international midfielder Ballack seized on a loose ball to drive home the winner in the second period of extra time and keep Chelsea on course for an unprecedented quadruple of trophies.