Sunderland manager David Moyes said his team needed to go on a winning run to escape relegation but they could be without top scorer Jermain Defoe for Tuesday's Premier League trip to revitalised champions Leicester City.
Sunderland are bottom of the table and seven points from safety, having won just one of their last 12 league games. Saturday's 1-0 defeat by Watford leaves them desperate for a win at Leicester, who are on a four-game winning run in the league.
Leicester, who were flirting with relegation themselves before Claudio Ranieri was sacked in February, are undefeated under new manager Craig Shakespeare and have climbed to 13th in the table, six points above the drop zone.
"In the position we're in, it's going to take a really good go. We need to start winning games back to back," Moyes told a news conference on Monday.
"Leicester are in good form but they have some big games coming up. Hopefully we can catch them on an off night. While there's still a mathematical chance, we need to keep going. This was always going to be a pivotal week."
The task ahead of Moyes has been complicated by the possibility of Defoe missing the match. The England international has scored 14 goals for Sunderland this season.
The club's next highest scorer, Victor Anichebe, has scored three goals. "Jermain Defoe didn't train yesterday. I can't give you any more of an update than that," Moyes said.
He also apologised for comments he made to BBC reporter Vicki Sparks after Sunderland's game against Burnley on March 18. Moyes was caught on camera telling Sparks after an interview, "You still might get a slap even though you're a woman. Careful the next time you come in."
British media reported that the manager's comments were made after Sparks asked him whether having Sunderland owner Ellis Short in the stands during the Burnley game had increased the pressure on him.
"It was in the heat of the moment, I deeply regret the comments I made," Moyes said on Monday.
"It's certainly not the person I am and I accept it was a mistake. I've spoken to the BBC reporter who accepted my apology and hopefully we can now move on.
"If you look at my character and personality it couldn't be further from the truth. It can happen to managers young and old. It can be difficult being put in front of the cameras so soon after the games."
(Reporting by Simon Jennings in Bengaluru; editing by Mark Heinrich)