Tom Wood's 78th-minute try helped Northampton Saints narrowly beat Leicester Tigers 21-20 to reach the Aviva Premiership final in a thriller at Franklin's Gardens tonight.

Manu Tuilagi and Ben Youngs crossed to help Leicester into a 17-6 half-time lead, but the unfancied Saints fought back bravely in the second period and completed their comeback two minutes from time.

The Tigers had three players sin-binned, while Salesi Ma'afu was sent off for Northampton, who were winless in their last nine matches against Leicester but upset the form book in an enthralling contest.

Toby Flood kicked the first points of the game with a 10th-minute penalty, and although Stephen Myler responded in turn to level the scores, Northampton's parity lasted only two minutes.

Despite being a man down, with Niki Goneva having been shown a yellow card, England international Tuilagi touched down for Tigers on 25 minutes, and Flood added two more points with the boot.

Flood confidently converted again on 34 minutes, after Youngs had scored Leicester's second try, although Myler had kicked another successful penalty to ensure Saints were only 11 behind at the break.

It appeared as though the East Midlands outfit were on their way to Twickenham when they withstood Northampton's early second-half barrage and survived Dan Bowden's spell in the sin bin unscathed.

Ma'afu's punch on Tom Youngs saw the Australian prop sent off on 58 minutes, but Saints defied their numerical disadvantage when George North charged over from close range following a lineout.

Myler converted to cut Leicester's lead to one, but that was soon increased to four courtesy of a 72nd-minute penalty from Owen Williams, who had replaced Flood at fly-half only moments earlier.

However, Northampton had one more rally in them as Wood crossed in the corner after the ball had been switched from right to left, with Myler's missed conversion irrelevant as Saints won by a single point.

Jim Mallinder's side will face either Saracens or Harlequins in the final at Twickenham.