Phillips is to undergo an operation next week after suffering a tear to the anterior cruciate ligament and a grade-two tear to the medial collateral ligament.

He will miss the Ospreys challenge for a domestic and European Cup double and Wales’ summer tour to South Africa.

The injury is a cruel twist of fate for Phillips, who established himself ahead of Dwayne Peel as Wales’ first-choice scrum-half during their Grand Slam campaign.

Phillips was shortlisted as one of the six players of the RBS 6 Nations - a prize won by his Ospreys team-mate Shane Williams - and his form saw him preferred to Justin Marshall in the starting line-up for Saturday’s 30-3 victory at the Millennium Stadium.

Phillips tried to continue after suffering the injury but was replaced by Marshall in the second half.

Ospreys physio Chris Towers said: “Mike has damaged two ligaments, causing considerable laxity in the knee.

“Having seen the specialist today, the opinion is that the treatment of choice for him is to undergo surgery to repair both ligaments in order to ensure the best functional outcome.

“The injury happened when he received an impact to the outside of his right knee. He wanted to stay on and continue playing, which is an indication that Mike is a pretty tough cookie, but it was clear that there was a problem and our worst fears have been confirmed.”

Towers is confident Phillips will return to action in time for Wales’ autumn internationals against South Africa, Canada, New Zealand and Australia - and be as good as new.

“These are relatively common injuries in contact and collision sports and unfortunately in this instance, completely unavoidable,” Towers continued.

“The good news is there are plenty of top-flight rugby players and Premiership footballers out there who have suffered similar injuries and are back doing the business as good as ever, and there is no reason to think that Mike should be any different.

“After his operation he will be looking at a six-month rehabilitation period, which means that hopefully we’ll be seeing him back in action by October.”