Tottenham's grip on a top-four place in the Premier League is suddenly under threat after falling to another loss on Saturday, while the fight to avoid the final relegation spot tightened as well.
Southampton's 2-1 comeback win over Tottenham extended Spurs' winless streak in the competition to four games and left both ends of the table looking more unpredictable.
Tottenham is now just three points ahead of fourth-placed Manchester United ahead of its game at Arsenal on Sunday, with the Gunners just a further point back. Sixth-placed Chelsea, meanwhile, is five points behind Spurs with two games in hand — meaning Tottenham's hold on a Champions League spot is in real peril after three losses and one draw in its last four matches.
James Ward-Prowse scored the winner for Southampton with a free kick in the 81st minute to keep Southampton two points ahead of 18th-placed Cardiff, which also earned a crucial 2-0 home victory over West Ham.
CARDIFF 2 - 0 WEST HAM
Cardiff showed it intends to fight to stay in the Premier League as it kept in touch with fellow strugglers by beating West Ham 2-0
Junior Hoilett and Victor Camarasa scored in either half as Cardiff ended a run of three successive defeats with a victory that was rarely in doubt from Hoilett's fourth-minute opener.
But Southampton's comeback win against Tottenham leaves Cardiff in the bottom three and two points from safety.
Although Cardiff remains in the relegation zone with eight games left, this victory will offer hope to Neil Warnock's side that it can survive.
Half of those games are against top-six sides — Chelsea and Liverpool at home and the two Manchester clubs away — but there could be enough opportunities to pick up points from sides around the Bluebirds.
Manuel Pellegrini's mid-table Hammers have lost five of their last six on the road without scoring.
Newcastle also rallied from two goals down to beat Everton 3-2, while Brighton beat Crystal Palace 2-1 in the early game — results that mean that Newcastle in 13th is only six points ahead of Cardiff in 18th, the final relegation spot.
Fulham and Huddersfield both look doomed, though, after losing again. Last-placed Huddersfield lost 2-0 at home against Bournemouth and is now 16 points from safety with eight games to go, while Fulham remained just three points ahead in 19th after losing 3-1 at Leicester.
Later, leader Manchester City had a chance to go provisionally four points clear of Liverpool with a win over Watford.