Week after week, month after month, David O'Leary has talked of the moment when Harry Kewell would at last "explode" on to this season's stage. O'Leary will have been wanting a date earlier than the first week of December, but Kewell made the wait worthwhile last night with a goal that amounted to an eruption of talent on a dormant landscape.
Nineteen uneventful minutes had passed when Kewell collected a loose ball 30 yards from his own net. In the blink of an eye the Australian had surged down the pitch and scored a goal of uplifting quality, one that sent Leeds on their way into the last 16.
O'Leary did not carry through his threat of naming three substitutes, giving Jamie McMaster and Frazer Richardson a taste of first-team squad life.
The shortage meant another start on the right wing for Alan Smith - though in attack rather than midfield - and another deluge of praise for Smith's commitment.
"Willing to sacrifice himself for the team," was how O'Leary described Smith's efforts at Fulham on Sunday in an unusual position. "That's what we need at Leeds United if we are going to be successful," said O'Leary.
"It's no good having people who say: 'That's not my position, I'm not going to play there.' "
The latter was interpreted as a dig at Olivier Dacourt, who apparently refused to play on the right at Craven Cottage before the job was offered to Smith.
In a strange opening when it seemed that Leeds might swamp Grasshoppers at any time, it was finally Dacourt's pass that sent Kewell on his way.
It actually originated close to the Leeds area with a Grasshoppers free-kick. Dacourt won the loose ball, but when it arrived at Kewell's feet there was still three-quarters of the pitch left.
But the Swiss had come forward in numbers and Kewell sized up the situation immediately. Pushing the ball past Mihai Tarrache, Kewell glided into the opposition half. There was still a token Zurich defender to go, Roland Schwegler, but Kewell sprinted by and then lifted a strong right-foot shot over Peter Jehle into the top corner.
That made it 3-1 on aggregate and had Kewell's superb 25-yard inswinger not hit Jehle's crossbar 10 minutes later then it would have been over, but Grasshoppers came back into the game in first-half injury-time when Richard Nunez profited from a series of mistakes from Rio Ferdinand, Danny Mills and Nigel Martyn.
Yet there was still time in that period for Keane to restore Leeds' advantage with a cool shot after a flick from Mark Viduka.
Viduka almost added a bizarre third past the hour and the same player produced a fine block from Jehle with a stinging drive soon after. And at the other end, there were two anxious moments for Martyn and he dealt with neither convincingly. The watching Sven-Goran Eriksson will have noted Martyn's sluggish dive as Nunez grabbed a second goal.
LEEDS UNITED: Martyn, Kelly, Ferdinand, Mills, Harte, Smith, Batty, Dacourt, Kewell, Keane, Viduka. Subs Not Used: Robinson, Wilcox, Duberry, McMaster, Richardson. Booked: Batty. Goals: Kewell 19, Keane 45.
GRASSHOPPERS: Jehle, Schwegler, Hodel, Castillo, Smiljanic (Morales 74), Cabanas (Ippoliti 66), Diop, Tararache, Gerber (Mwaruwari 59), Nunez Pereyra, Chapuisat. Subs Not Used: Benaglio, Baturina, Spycher, Jaggy. Booked: Diop. Goals: Nunez Pereyra 45, 90.
Referee: F de Bleeckere (Belgium)