St Mirren's 1-0 victory in Paisley came a week after they lost to the same opposition in the Clydesdale Bank Premier League.

In the 55th minute Celtic captain Stephen McManus felled Craig Dargo inside the box and the English striker sent Artur Boruc the wrong way from the spot.

Celtic threw everything forward to keep their hopes of a domestic treble alive but the Buddies defended resolutely to book their semi-final spot.

Falkirk joined St Mirren in the semi-finals after beating Inverness at the Caledonian Stadium, also by a 1-0 margin.

The turning point of the match came just after the half-hour mark when Lionel Djebi-Zadi was sent off for a last man foul on Carl Finnigan.

The Falkirk striker took the penalty himself and smashed the ball past Ryan Esson.

Aberdeen encountered First Division resistance as Nick Phinn's late equaliser earned Dunfermline a 1-1 draw and a quarter-final replay.

The Dons looked to have given themselves the chance of atoning for last year's semi-final defeat to Queen of the South when Sone Aluko capitalised on some sustained pressure to score just after the hour mark.

But, with nine minutes left at East End Park, Phinn bundled the ball over the line from close range to force a replay.