Shane Williams claims his second try against Ulster

Shane Williams has given his fellow Ospreys a sharp reminder to clean up their discipline before facing Saracens in the Heineken Cup.

The Welsh region are favourites for that quarter-final encounter at Vicarage Road.

But wing Williams says they must learn from Friday's 32-7 Magners League win over Ulster at Liberty Stadium.

Williams said: "There is a lot to work on. There were too many mistakes and at times our discipline was quite poor."

606: DEBATE Is Shane right to be worried about Ospreys' discipline?

The Wales Grand Slam hero and Six Nations player of the year was delighted to claim two more touchdowns against the Irish province.

But he says while Ulster made life difficult for the EDF Cup finalists, the Ospreys also let themselves down at crucial moments.

Williams said: "Our performance wasn't the best at times. Ulster made it very difficult for us and slowed down every possible ball.

"They made it very difficult for us to play our usual, open expansive rugby.

We certainly deserved the bonus points and in the end it was a good performance Shane Williams

"There were a lot of mistakes and at times our discipline was poor and we gave away silly penalties.

"It's something we've addressed in the past and it's something we should really think we have nailed down.

"But we certainly deserved the bonus points and in the end it was a good performance."

Williams believes that can augur well for the clash with Saracens and EDF final against Leicester at Twickenham the following week.

"It's brilliant to get the momentum. We've got a massive game against Saracens next weekend and we needed the win.

Mike was probably looking forward to more rugby and the way he was playing didn't want the season to end Shane Williams

"We also needed to feel good about the way we played and did that at times. Now there are some little things to work on in the week."

Williams is also hoping Ospreys success can boost injured Mike Phillips' morale. The scrum-half has been ruled out for six months with knee ligament damage.

"You've got to feel for Mike. He's had a great season and had a great Six Nations - he was one of the players of the tournament," said Williams.

"It's bad timing and I'm sure he'll be back sooner than expected. Unfortunately it's quite a bad injury and our hearts go out to him because he's had such a great season.

"He was probably looking forward to more rugby and the way he was playing didn't want the season to end."