Nick Evans today gave Harlequins a major boost in their bid to become Guinness Premiership champions by revealing he will be fit for the semi-final with London Irish.

The fly-half injured knee ligaments for the second time this season in the 6-5 Heineken Cup loss to Leinster but after intensive treatment, the All Black is adamant he will be okay for the clash at the Twickenham Stoop on 9 May.

Quins' 31-12 bonus-point victory over Newcastle guaranteed a home semi-final against Irish, who ensured their appearance in the play-offs with a 32-15 win at Worcester.

It has set up the biggest derby in London rugby this season with the prize being a Twickenham final against either Leicester or Bath.

Evans is relishing returning for the match and said: "I am going to be fit and was pretty close to being in the mix for the Newcastle game. Now, with a week off without a game, I can keep working on my rehab and be ready for the semi-final. I have a pretty good record in semis from my time in New Zealand and we all want the chance to battle it out for the title at Twickenham.

"This has been a fantastic season for Quins and a lot of credit has to go to Will Skinner, our captain, who reminds me a lot of Richie McCaw, the All Blacks skipper. Just like Richie, you can rely on Will to produce the goods every game and lead by example."

Dean Richards cannot understand why Skinner has not been picked for England. The Quins director of rugby said: "If you ask any of the other coaches they will agree that Will has been the form No7 in the Premiership."

Quins insist their semi-final preparations will not be disrupted by an investigation into their use of a blood replacement against Leinster.

Evans, having gone off with his knee problem, was brought back on in the dying moments after Tom Williams suffered a mouth injury. Evans subsequently missed a drop-goal effort but Leinster were still angry and there have been claims Williams was not injured.

However, Quins insist they have nothing to hide from the European Rugby Cup investigation and the club's chief executive, Mark Evans, said: "I am not concerned about speculation over the incident. I am confident about how this will work out. We're absolutely fine."

Irish, meanwhile, should have Elvis Seveali'i, who has been out with a calf strain, available for the semi-final to boost their already potent backs.

With captain and lock Bob Casey playing again after a bicep injury it means the Exiles are almost at full strength and director of rugby Toby Booth is now urging his men to make a final push for honours.

"We achieved our minimum standard this season by qualifying for the Heineken Cup," he said. "What are you in this game for? You are in this game not to come second or third, you are in it to win something.

"That is why I am just pleased we have a ticket in the lottery at the moment."