Director of rugby Conor O'Shea says Wales international Jamie Roberts will give his side the edge in big games as Quins bid to put a miserable campaign behind them next term.

A young Harlequins line-up slipped to a final day 37-21 defeat at Newcastle Falcons on Saturday as the Stoop outfit finished a lowly eighth in the Premiership table.

Roberts signed a two-and-a-half year deal to switch to west London from French Top 14 side Racing Metro this week in a move that will coincide with him starting a part-time masters degree in medical science (surgery) at Cambridge University.

The 28-year-old former Cardiff Blue turned down a return to the Welsh regions, but will still be available for Wales internationals after the World Cup under the terms of his Harlequins contract.

Quins, ravaged by injuries this term, have struggled to make an impression in all competitions over the past season and O'Shea is expecting Roberts' arrival to make an immediate impact.

"He is massively ambitious on and off the field. Everyone involved with the club is excited by somebody of his ability and stature," he said.

"We've had our well documented injuries and unavailabilities this season, but we have an exciting way of playing.

"We want to be at the top. Players like Jamie will make sure little things in matches make the difference.

"Little things in big matches make the difference. Big game players come up with big plays and he is that."

Quins' miserable domestic season mean they will not be playing in the European Champions Cup next term and instead will be in the second tier Challenge Cup competition.

But Roberts expects the club to return to the form that saw them crowned Premiership champions in 2012.

"My desire to compete and win at both club and international level remains as strong as ever and the brand of rugby Harlequins play will challenge my skill set and no doubt help me improve as a rugby player," he added.

“You look at the calibre of the Harlequins squad and the coaching set up. They are a team that are going to be competing at the top level year in year out and that was a huge factor in my decision to sign."

The plus point from the weekend's defeat was a promising debut from England U20 international centre Joe Marchant.

And O'Shea anticipates Roberts to play a key role in his development.

"As a role model to all of our players, Jamie will be someone we can all learn from," he said. 

“We know we won't see Jamie in the Harlequins jersey for a while yet.

"But when we do I know he will be a massive contributor to the history of this club, the development of our team and the development of young players like Joe Marchant and Harry Sloan."