So much for David O'Leary's dream of emulating his beloved Arsenal. After five successive defeats on their European travels, Leeds's bright-young things experienced a long-overdue victory last night.

The losing streak had stretched back to the Bernabeu last season, but was washed away in less auspicious surroundings and perilously late into this game. Just 17 minutes remained when Ian Harte's free-kick cancelled out Stephane Chapuisat's opening goal; Alan Smith's smart second just six sodden minutes later virtually guaranteed the Yorkshiremen safe passage into the fourth round.

The Leeds manager could only fill four of the seven places on his bench, but even so his selection hardly suggested he had scraped the barrel and should have claimed early reward. Eirik Bakke charged down Boris Smiljanic's clearance but, after the ball had squirted into the area, Smith skied his shot high and wide.

Unperturbed, Olivier Dacourt then cut inside Mihai Tararache and dragged a shot just wide before Harte worked himself some space on the left to cross to the far post, where Smith mistimed his jump and the ball dribbled behind.

The home side were visibly shaken by the onslaught, but their dishevelled defenders survived and soon their most potent attacker grabbed an unlikely lead. Chapuisat once conquered Europe with Borussia Dortmund; here he cut inside from the right flank and lashed a 25-yard shot which skimmed off the turf and inside Nigel Martyn's right-hand post.

Smith's immediate riposte was ruled out for offside and he was soon outstripping Bouba Diop before slicing over. But the visitors' earlier authority - David Batty's fearless sliding challenges through the mud aside - had been washed away.

Instead Chapuisat strutted through the puddles, leaving Dominic Matteo red-faced as he turned sharply to curl another left-foot effort just wide. Richard Nunez and Benjamin Mwaruwari provided eager support, marauding forward at will, with the former seeing his free-kick tipped unconvincingly away by Martyn.

The England goalkeeper had been unconvincing during the first half, wallowing in a muddy six-yard box while Grasshoppers peppered his g but after the interval he emerged from the deluge to keep Leeds afloat.

Diop roared forward and, with no sign of a challenge, had the 35-year-old sprawling desperately to save his low shot. The Senegalese midfielder then slipped Ricardo Cabanas into space only for Martyn to intervene, while Nunez's long-range free-kick had to be turned aside.

But the goalkeeper's best was still to come. A messy scrap in midfield saw the ball run kindly through for Nunez and the Uruguayan was tugged by Rio Ferdinand just outside the area. The official, behind play and with little help from his assistants, flashed yellow and awarded a penalty.

Nunez had scored a hat-trick at home to FC Twente in the last round, but he fluffed his lines here. Martyn flung himself to his left to turn the shot away, blocked a rebound and Cabanas blazed the follow-up over.

In truth, the locals should have seen the turnaround coming. There were signs of defensive frailties when Harte's cross had defenders all in a dither and Pascal Castillo's sliced attempt to clear forced Peter Jehle into a smart save.

As it was, with Grasshoppers still recovering from the penalty miss, Leeds rallied to score twice within six frantic minutes. Tararache's crude challenge on Dacourt earned the visitors a free-kick which Harte curled into the top corner to the delight of the 1,108 chilly travelling fans. And Grasshopper wilted again when Dacourt's scuffed shot bobbled in the goalmouth and trickled to Smith. The striker, his earlier misses forgotten in an instant, turned smartly and poked the winner into the net.

GRASSHOPPERS: Jehle, Bouba Diop, Hodel, Smiljanic, Schwegler, Nunez Pereyra, Cabanas (Baturina 74), Tararache (Petric 88), Castillo, Mwaruwari (Gerber 80), Chapuisat. Subs Not Used: Huber, Spycher, Morales, Jaggy. Booked: Tararache. Goals: Chapuisat 17.

LEEDS UNITED: Martyn, Mills, Ferdinand, Matteo, Harte, Bakke, Batty, Dacourt, Wilcox, Smith, Keane. Subs Not Used: Robinson, Kelly, McPhail, Duberry. Booked: Wilcox, Mills, Ferdinand. Goals: Harte 73, Smith 79.

Referee: L Batista (Portugal).