Harlequins were dealt a major slice of luck yesterday as Llanelli Scarlets pulled off a surprise home win over Stade Francais to guarantee that Dean Richards's men will top Pool Four of the Heineken Cup.

Richards was fuming on Saturday after claiming match officials bungled the substitution of Nick Evans as the fly-half was preparing to take a 73rd-minute penalty that would have brought Harlequins to within three points of Ulster.

Chris Malone was rushed on, much to Richards's annoyance, and proceeded to miss the attempt at goal before having a kick charged down moments later that led to Rory Best's decisive try for the Ulstermen.

"Nick was cold and struggling a bit but at the same time the idea was that he take the kick," Richards said. "I said to the fourth official, 'You can't do this,' but he said the referee was insisting I put Chris on. I think it made a difference."

The 21-10 defeat had looked to have made next Saturday's visit of the Scarlets a must-win game for Quins, until yesterday's timely intervention from Nigel Davies' men.

Richards will now be afforded the rare luxury of being able to rest his key players.

London Wasps are getting stronger by the week, claims Josh Lewsey.

Wasps, who had a dismal start to the campaign, kept alive their hopes of reaching the last eight of the Heineken Cup by beating Leinster 19-12 at Twickenham on Saturday .

That was their sixth win in seven games. "We're building momentum and there is a really great feeling at the club at the moment," he said.

In the European Challenge Cup, Saracens booked their place in the quarterfinals with a 36-19 win over Italian side Viadana. London Irish are also through after beating Connachtat 75-5.