|European Rugby Champions Cup - Pool 3: Scarlets v Ulster|
|Venue: Parc y Scarlets Date: Sunday, 14 December Kick-off: 17:15 GMT|
|Coverage: Live commentary on BBC Radio Wales, BBC Radio Ulster and the BBC Sport website from 17:00 GMT|
Scarlets centre Scott Williams says European Champions Cup Pool 3 is "wide open" following Leicester's 25-21 win against defending champions Toulon.
The Llanelli-based region are bottom of the table, five points behind leaders Toulon with three games to go.
Wayne Pivac's side host Ulster on Sunday, a week after losing 24-9 to them in Belfast, and Williams, 24, says it is a crucial match.
"It's going to be a massive game for us this weekend," said Williams.
"We've been harsh on ourselves this week.
"The boys are ready to put things right because we owe ourselves and our supporters a performance."
|Scarlets' remaining Champions Cup matches|
|Sunday, 14 December: Ulster (home)|
|Saturday, 17 January: Leicester (away)|
|Saturday, 24 January: Toulon (home)|
Scarlets have injury worries over full-back Liam Williams (shin) and flanker James Davies (ankle) ahead of the match.
Both players were sin-binned in Belfast and centre Williams told BBC Radio Wales that discipline is one area his side hope to improve on from last week's defeat.
"Playing 20 minutes of the game with 14 men is not ideal, so we've just got to make sure that we cut those things out," said Williams.
"We also have to make sure that we execute the game to the best of our ability."
"The best thing is that we have a chance to put things right this weekend," said Williams.
"Normally you have to wait six to eight months to play the same team.
"The boys are raring to go."