Northampton (6) 19 Try: Human Con: Drahm Pens: Drahm (4) Leeds (17) 24 Tries: Shelley, Regan Con: Ross Pens: Ross (3) Drop: Ross Powergen Cup photos

Tries by Mike Shelley and Mark Regan as well as the accurate kicking of Gordon Ross kept the Tykes in front.

Saints kept in the game with a 50th-minute score by Wylie Human, which set up an exciting finale.

But Northampton's chances effectively ended when Mark Robinson was sent off for stamping on Regan's head.

The New Zealand scrum-half could face a ban of six to eight weeks for his indiscretion 10 minutes from time.

"We're very disappointed," admitted Saints coach Budge Pountney. "Leeds were the better side and they thoroughly deserved to win."

An often ill-tempered match was dominated by the boot early on as Shane Drahm and Ross swapped penalties.

But it was Leeds who proved the more creative in the first half, while Northampton's game was littered with errors.

Both sides had early chances to score only for Diego Albanese and Grant Seely to knock the ball over the line with their separate try attempts.

Saints were woeful -beaten by a far better team on the day From Louisa Have your say on Scrum V

The Tykes' pack piled on the pressure, which eventually led to the sin-binning of Darren Fox (for repeatedly coming in from the side of the maul) and the visitors' first try.

Maul after maul was fended off before Shelley finally found a way through.

Saints needed a strong start to the second half but were in disarray from the outset. And continual fumbles by their players eventually cleared the way for Regan to score.

Northampton, though, forced their way back into the game with half an hour left to play.

Ben Cohen, who produced an impressive display in front of England coach Andy Robinson, opened space for Human to ground the ball from his hack ahead.

A final would be massive for the club and being in the semis will be great exposure Leeds coach Phil Davies

And moments later Cohen stopped a certain try when he smothered a flying Phil Christophers inches short of the try line.

Drahm set up an exciting finale when his penalty on the hour left Leeds with a 24-16 advantage.

But the pressure eased massively for the home side when Robinson was sent off for stamping on Regan's face.

Despite the man disadvantage, Saints were the more hungry as the clock ticked on, but they failed to find a way through.

"I felt we were hanging onto it a bit rather than scoring tries to bury them," Regan said afterwards. "That was frustrating but we got the win in the end."

Northampton: Reihana; Human, Cohen, Stcherbina, Tucker; Drahm, Howard; Emms, Richmond, Budgen; Seely, Browne; Blowers, Fox, Beattie.
Replacements: Van Wyk, Morris, Lord, Soden, Robinson, Grayson, Vilk.

Leeds: Stimpson; Balshaw, Christophers, Snyman, Albanese; Ross, Dickens; Shelley, Regan, Kerr; Murphy, Palmer; Morgan, Parks, Rigney
Replacements: Gerber, Rawlinson, Dunbar, Uys, McMillan, Wright, Rees.