Kelechi Iheanacho hit a hat-trick as Leicester thrashed doomed Sheffield United 5-0 to move into second place in the Premier League, while Brighton improved their hopes of avoiding relegation with a vital win against Southampton on Sunday.

Leicester showed no mercy to bottom-of-the-table United in the visitors' first match since Chris Wilder's departure on Saturday.

Wilder, who led United from third-tier League One to the Premier League, left by mutual consent after several days of speculation about his future.

United, managed by interim boss Paul Heckingbottom, look destined for relegation after failing to build on last season's impressive first campaign back in the top flight.

The Blades, 14 points from safety with only nine games left, have lost six of their last seven league games.

Leicester pushed them closer to the Championship with their biggest win this season. Nigerian striker Iheanacho opened the floodgates in the 38th minute at the King Power Stadium with a close-range finish from Jamie Vardy's pass after a flowing move.

Iheanacho's third goal in his last three games was followed by Ayoze Perez's fine strike from the edge of the area in the 64th minute.

Iheanacho scored again in the 69th minute from Vardy's cross and completed his treble with a 25-yard blast past Aaron Ramsdale.

Ethan Ampadu's own goal from Vardy's effort in the 80th minute sealed the rout for Brendan Rodgers' side, who moved above Manchester United and within 15 points of runaway leaders Manchester City.

Spurs face Arsenal test

Brighton edged three points clear of third-bottom Fulham with a game in hand after a frenetic south-coast derby at St Mary's, winning 2-1. It was a first win in eight games in all competitions for Graham Potter's side since they beat Tottenham in January.

The Seagulls are one point above fourth-bottom Newcastle, who travel to Brighton for a crucial clash in the relegation battle next weekend.

Brighton took the lead through Lewis Dunk in the 16th minute. Fraser Forster made a fine save to keep out Neal Maupay's shot but Dunk's towering header from the resulting corner flashed past the Saints keeper.

Southampton drew level in the 27th minute when Dunk could only help Ryan Bertrand's header into the path of Che Adams, who volleyed home at the far post.

But Brighton went back in front in the 56th minute as Leandro Trossard produced a fine finish from Danny Welbeck's lay-off.

Later on Sunday, Tottenham, unbeaten in the last five north London derbies dating back to 2018, will aim to bolster their top-four bid by recording a third successive victory against bitter rivals Arsenal.

Jose Mourinho's side have won their last five games in all competitions and can close to within three points of fourth-placed Chelsea with a game in hand if they win at the Emirates stadium.

West Ham are also in the race to qualify for the Champions League via a top-four finish.

David Moyes' side can move level on points with Chelsea with a game in hand if they beat Manchester United at Old Trafford.

The Hammers have won eight of their last 11 league matches, while United need the points to cement their own top-four ambitions.

United dropped to third after Leicester's victory, but Ole Gunnar Solskjaer's men would go back above them with three points against West Ham.

Former United boss Moyes, sacked by the Old Trafford outfit in 2014 after less than a season in charge, will be returning to his old club for the second time this term following their FA Cup defeat last month.