Arsenal had gone 21 games unbeaten against their arch-rivals with Tottenham's last win coming back in November 1999.
But Spurs managed to end that dreadful record in style as Jermaine Jenas, an own goal from Nicklas Bendtner, Robbie Keane, Aaron Lennon and Steed Malbranque's strike ensured they would be returning to Wembley for the final on February 24.
Tottenham got off to a dream start when Jenas opened the scoring after just three minutes.
Dimitar Berbatov laid the ball into the England midfielder who drilled a shot from the edge of the box which flew past Lukasz Fabianski into the corner of the net.
Things got even better for the home side when they doubled their lead on 27 minutes.
Jenas planted a high free-kick into the box and Bendtner rose to meet the ball with Michael Dawson, but the Arsenal forward somehow managed to direct a header past his own keeper.
Tottenham could have wrapped the game up three minutes later when another high ball from Jenas picked out Berbatov, who broke the offside trap and raced towards goal but saw his shot come back off the post.
Arsenal came close to pulling a goal back on the half-hour mark when Bacary Sagna's close-range header was tipped over the bar by Tottenham keeper Radek Cerny.
Keane added a third for Tottenham three minutes into the second half.
Aaron Lennon played the ball into the Republic of Ireland striker and he struck his right-foot shot through the hands of Fabianski and into the corner of the net.
Arsenal refused to lie down and Bendtner was unlucky not to make up for his earlier mistake when he hit the woodwork just a minute later.
Theo Walcott played the ball back to the Denmark striker who saw his shot come back off the bar. The rebound fell to Fabregas but he fired his shot straight at Cerny.
Tottenham finally put the game beyond their north London rivals when Lennon grabbed a fourth on 60 minutes.
Keane released the England winger into the box and he made no mistake in sliding the ball past Fabianski.
Arsenal substitute Emmanuel Adebayor pulled a consolation strike back for Arsene Wenger's side on 70 minutes when he fired a blistering shot which sailed past and Cerny into the roof of the net.
But Malbranque made it a night to remember for Tottenham when he scored the fifth in injury time after tapping home a cross from Jenas.