Sam Allardyce believes West Brom must stop one of the Premier League's best strike partnerships in Jamie Vardy and Kelechi Iheanacho to keep their survival hopes alive.

Vardy and Iheanacho have scored 29 goals between them this season as Leicester have climbed to third place in the Premier League and reached their first FA Cup final since 1969.

Iheanacho scored his 15th goal of the season as Southampton were 1-0 beaten in Sunday's semi-final, with the in-form Nigeria striker set up by the seemingly-ageless Vardy.

"We've got to look after maybe the best pairing in the Premier League at the moment," West Brom boss Allardyce said ahead of Albion's trip to Leicester on Thursday.

"Iheanacho and Vardy are probably two of the most dangerous forwards in the Premier League.

"Part of our task is to try and keep them from scoring a goal and making sure we give ourselves a chance of winning the game.

"That will be a key area for our defence to try and look after those two.

"Getting to the FA Cup final will have lifted Leicester's spirits because that is a major achievement.

"On the back of that will make life difficult for us, and they've still got to get points to maintain their Champions League position."

Back-to-back wins over Chelsea and Southampton have given West Brom a glimmer of hope that can avoid relegation after appearing to be doomed all season.

Albion remain nine points from safety with seven matches to play, but Allardyce's side do have a game in hand on 17th-placed Burnley.

"We are reliant on teams above us losing games," Allardyce said.  "We're in a position where we can ill-afford to lose more than one of our last seven games.

"If we're lucky, maybe two, and then we'd have to win all the others. But win this one and we stay in touch with the teams above us.

"We can only concentrate on the way we've played recently and maintain that standard.

"If we do that it will make everyone have a little look at us and say: 'Wow! They're having a go those lads'. We want to have a go right to the very end."

Allardyce, not for the first this time season, is bemused that West Brom have been told to play a Premier League fixture on a Thursday night.

The same thing happened last month when Albion lost 1-0 to Everton at the Hawthorns.

"We wanted to play (Sunday's opponents) Aston Villa at the weekend as neither of us had a game," Allardyce said.

"We were refused that request sadly. I don't know why, but probably it was for other reasons than football.

"We couldn't play on Tuesday as Leicester played on Sunday. I think we've fallen foul of the FA Cup again, as we did against Everton.

"But we could have easily played this game on Wednesday. Having to play on Thursday and Aston Villa on Sunday causes us massive problems."