Old foe can inspire Sale to give Quins' young guns their sternest test

O'Shea out to stop history repeating itself – 15 years after Diamond last cut Harlequins down to size

These are heady times for the Harlequins.

With four wins out of four, the men from the Twickenham Stoop top the Aviva Premiership table with the only perfect record – looking down on the wounded Leicester Tigers and the crestfallen Northampton Saints, both beaten three times already in the midst of the World Cup call-up period.

Not since the 1996-97 season have Quins made such a mightily impressive start. On that occasion, with Will Carling and Keith Wood in tow, they opened with a run of six victories before coming unstuck against a tough-nut Sale side featuring Steve Diamond at hooker. The opponents at the Stoop this afternoon? A Sale team galvanised under the direction of Diamond, lying fourth in the table with three wins out of four.

"I haven't been surprised at how well Sale have been doing – not with Steve Diamond in charge," Conor O'Shea, Harlequins' director of rugby, said. "He's an incredibly knowledgeable rugby person and you can see it in the way his team play. They play with a massive amount of energy and enthusiasm and with a heck of a lot of width. They punish teams from deep. It's going to be a big test for us."

It was a big test for Quins at Sixways last Saturday. On the back of a 42-6 steamrollering of Gloucester, they were out of sorts for the opening 60 minutes against Worcester, trailing 15-3 going into the final quarter – and yet they managed to get their act together in the nick of time, Kiwi fly-half Nick Evans converting a penalty try to clinch a 17-15 victory.

"That was as satisfying a win as the one against Gloucester in many ways," O'Shea reflected. "It was away from home and we found a way back into the game. You have to win when you're not playing so well. Last season we lost a lot of games by less than a score."

The 2010-11 campaign was Harlequins' first full season with O'Shea – the former Ireland full-back and RFU academy director – installed as the long-term successor to Dean Richards. They ended seventh in the table but finished with a trophy-winning flourish, lifting the Amlin Challenge Cup after claiming the scalp of Munster in a Limerick semi-final and beating Stade Français in a dramatic final in Cardiff.

In the process, O'Shea laid the foundations for a new youthful, dynamic, Anglocentric playing structure at the Stoop. All but two of Quins' matchday 23 today are English-qualified, and ten of the starting XV are graduates of the club's academy system.

"You always want your players like Nick Evans and [Samoan back row] Maurie Fa'asavalu, because they add a different influence," said O'Shea. "But, by and large, the drive for this club is to grow its own players, to recruit English players where we can, and keep the squad together over a long period of time."

In the short term, Quins have not been as severely affected as Leicester (who they meet at Welford Road a week today) by World Cup commitments. However, winger Ugo Monye is on the casualty list this afternoon. Will Skinner is fit again and on the bench while, after two man-of-the-match winning performances, Luke Wallace keeps his starting place on the openside flank. One of O'Shea's emerging young guns, he turns 21 tomorrow.