EDF Energy Cup semi-finals: Marshall law keeps Ospreys flying

The joke doing the rounds in Wales when Warren Gatland picked a record 13 Ospreys for the opening Six Nations match against England was that the three players he wanted most were Justin Marshall, Filo Tiatia and Marty Holah.

Marshall at scrum-half and back-rowers Tiatia and Holah have provided a holy trinity of New Zealand nous at the hub of the Ospreys' march to a second successive EDF Energy Cup semi-final in Cardiff next Saturday and a first Heineken Cup quarter-final in Watford two weeks later; both against Saracens. Marshall predicts he will have to share top billing with Wales' incumbent No 9, Mike Phillips – they may start one tie each – but the former All Black rates the Kiwi connection as crucial to the Welsh region's pursuit of superpower status.

"The experience the three of us have got of big games in New Zealand can't be coached," said Marshall. "The Ospreys are full of young players and the balance with us adds something different. It causes the selectors headaches. I always know the lines Filo and Marty are running are the ones I'm looking for."

Marshall has watched Wales's progress with interest. "Wales under Warren Gatland look a lot less rudderless than last year, they have direction and purpose. But I'd say – and from the noises he has made, Gatland realises – that the standard of the Six Nations has been pretty average. Wales go to South Africa in the summer, then in the autumn they play the Tri-Nations, which will be the true test."

As for the Ospreys, their two Magners League titles in 2005 and 2007 have not quelled constant speculation over the future of their head coach, Lyn Jones.

Marshall pinpoints unsatisfactory Heineken Cup performances away to Gloucester and Bourgoin as evidence of the Ospreys' shortcomings. Then there was the EDF final against Leicester last year, when soft tries handed the trophy to the Tigers. "It was a bitter disappointment," Marshall said, "but it was a confidence-builder that we were able to compete with a superpower of European rugby. It's kicked on this season, and every big game is a stepping stone.

"Gloucester away and home [in the Heineken Cup] were significant. For 60 minutes at Kingsholm we were the better side, then juvenile mistakes left us without a point. It was a kick up the arse, and when we beat them back in Swansea it showed how much we'd learned."

Marshall joined the Ospreys in summer 2006 after a year at Leeds that followed his eminent Test career in New Zealand. His 42 appearances in two seasons prove him to be more than some flaky pension-seeker, and he has signed up for another year.

On a visit home recently for his brother's wedding, Marshall filmed a TV interview with his old half-back partner Dan Carter, who hinted at an imminent move overseas. The All Black captain, Richie McCaw, could do the same. "The reason I am still playing is I feel I am still contributing," said Marshall. "And with the Ospreys I think I'm helping grow a club that will be highly regarded in the future."