Scott Williams says the Scarlets’ Friday night Round 2 Champions Cup clash at home to Bath is a ‘must-win’ game after losing 21-20 to Toulon.

The Guinness PRO12 champions were forced to recover from an 18 point deficit after conceding two tries in the opening quarter-of-an-hour, but then scored the next 20 to take the lead and keep the three-time Champions Cup winners scoreless for 40 minutes.

But a 63rd minute penalty from Francois Trinh-Duc hauled the home side back in front and earned them the win.

“We just didn’t turn up in the first 20 minutes and that made it tough for us. We shouldn’t have given them that head start,” admitted acting skipper and Wales centre Williams.

“In the end we did enough to possibly win the game and I think we deserved to come away with something. It shows the strength of the squad we’ve got here that we felt we should have won the game.

“We need to keep the momentum going because we have a short turn around this week. We are home on Friday and we need to make sure we get a win.”

Bath beat Benetton Rugby 23-0 at home on Saturday and will be relishing such a short trip for their first away day. Williams won’t want his side to be caught cold at the start for a second weekend running.

He added: “We expected them to come direct at us and they went wide and caught us a bit narrow on their tries. We have got to make sure we cut out those errors next week.

“Maybe we’ve been given the short turn-around because people don’t expect us to go through, but I think we are the outside favourites to go through.

“We have got a good enough team and we showed that because after the first 25 minutes we were the best team.”

It was the Scarlets’ 10th successive away defeat in the Champions Cup, while Trinh-Duc’s late penalty stopped a repeat of the Round 1 defeat Toulon suffered at Stade Felix Mayol against Saracens last season – their only home defeat in six years in the competition up to this season.

“We were relieved to win in the end, but we knew the Scarlets would play some good rugby. We watched them in their campaign last season and they made us work for it,” said Toulon’s All Blacks World Cup winning centre Ma’a Nonu.

“We wanted to try and play in the first 40 and put some points on the board, but they came back in the second half. We got an early intercept but we slacked off after that. They kept coming back at us and made us work harder.”

Scarlets head coach Wayne Pivac is hoping his side will have learned from their poor start and admitted he had mixed emotions at the end after leaving with a bonus point.

“We didn’t get the fast start we wanted, but the second half was a bit better and we got ourselves into a position to win the game,” said Pivac.

“In the first 10 minutes of the game we turned over the ball too much and we kicked it away too often. We were soaking up tackles rather than dictating, but we will learn form that.

“It is mixed emotions in the end. We came here to win and I thought we had done enough to do that after a slow start.”