SUNDERLAND midfielder John Oster last night admitted that Sunday's Stadium of Light showdown with West Brom is a "must-win" encounter if the Black Cats are to secure automatic promotion to the Premiership.

Monday's 1-0 defeat at Ipswich has left Mick McCarthy's side nine points adrift of the second-placed Baggies as they look to avoid missing out on a top-two spot.

That gap would come down to six if Sunderland were to make it four home wins in a row at the weekend and, with them also having a game in hand on the top two, an automatic return to the top-flight is not yet out of the question.

But the Black Cats cannot afford a repeat of the anaemic Portman Road display that saw them fail to register a single goalscoring chance after falling behind to Tommy Miller's penalty on the stroke of half-time.

And Oster accepts that another failure to pick up all three points would represent a fatal blow to any hopes of overhauling either of the top two.

"Sunday's game with West Brom is a must-win game for us now," said the Wales international whose current contract expires at the end of the season.

"They drew on Monday and that makes our result at Ipswich even more disappointing because we could have closed the gap.

"We could have nicked a couple of points on them, but we've got them on Sunday and we need to win.

"We were all over them when we played them down at The Hawthorns and, even though we drew 0-0, we should have won comfortably.

"So we know we're more than a match for them and hopefully, if we play that well again, we can get the three points on Sunday."

Oster barely figured in the Sunderland first-team at all last year as, after being recalled from a loan spell at Grimsby by Howard Wilkinson, he was unable to hold down a place in the side.

He has been a virtual ever-present this term though, with his ability to play on either flank proving a valuable asset in the battle to break down opposition defences.

The 25-year-old has been a pivotal figure in Sunderland's recent run that has seen them play 12 games in just 30 days as a result of their FA Cup exploits.

Monday's limp defeat suggested that such a hectic schedule had finally caught up with the Black Cats, but Oster is refusing to use tiredness as an excuse for Sunderland's first defeat in ten league games.

"I wouldn't put the defeat down to being tired," he said. "I just think that we lacked a bit of quality in the final third for some reason.

"I don't think it was a tired performance. The manager's changed things around in recent weeks, but that's what he's had to do. He's chopped and changed his forward line and I think that's worked in all the games we've been playing."

McCarthy will have to change his midfield for Sunday's visit of West Brom as skipper Jason McAteer is suspended following his dismissal in the FA Cup semi-final defeat to Millwall.

Jeff Whitley is available again though after serving his five-match ban, and loanee Carl Robinson is set to battle it out with Paul Thirlwell for the other central midfield spot.

Robinson has provided a calming presence since joining from Portsmouth in the run-up to last month's transfer deadline, and the 27-year-old's experience could prove significant in the final hectic weeks of the campaign.

"I know Carl well from playing with him in the Wales set-up," said Oster. "I knew all about his qualities before he came here. He's come into the side and he's given us something a bit different at the heart of midfield.

"Our midfield has been great all season - people like Jeff Whitley have been outstanding - and the gaffer's got a lot of options now. It's good competition for places and that could be important in the last few weeks of the season."

McCarthy will monitor the fitness of striker Tommy Smith this week as he looks to recover from a virus in time to face West Brom.