Danish playmaker Christian Eriksen netted a superb 30-yard goal as Tottenham Hotspur downed Crystal Palace 1-0 on Wednesday to keep their Premier League title hopes alive.
Leaders Chelsea, who beat Tottenham 4-2 in the FA Cup semi-finals on Saturday, went seven points clear by beating Southampton on Tuesday, but Spurs' win trimmed the gap back to four points.
"It was unbelievable -- a very good performance," Spurs manager Mauricio Pochettino told Sky Sports at Selhurst Park.
"It was good to get the three points and be alive in the race for the title. The challenge is to keep going."
Eriksen struck in the 78th minute and Arsenal also left it late, Robert Huth's 85th-minute own goal giving Arsene Wenger's men a 1-0 win that left them four points off the Champions League places.
Palace had won six, drawn one and lost one of their previous eight league games and had the best of the first half against Spurs, Christian Benteke working Hugo Lloris and Andros Townsend firing over.
Pochettino took decisive action at half-time, sending on Son Heung-Min and Moussa Sissoko in place of Mousa Dembele and Victor Wanyama.
Palace lost Mamadou Sakho to a potentially serious injury in the 57th minute, the in-form centre-back, who is on loan from Liverpool, stretchered off after twisting his left knee.
"He has hyperextended the knee," said Palace manager Sam Allardyce, whose side remain 12th.
"It is certainly serious enough to keep him out for who knows how long. We won't know until we diagnose it, but if it is ligament (damage), it may be the end (of his loan spell)."
Dele Alli scored a glorious goal for Spurs at Selhurst Park last season, but he squandered a good chance shortly before the hour, volleying wide from Kyle Walker's right-wing cross.
Eriksen came to the rescue with 12 minutes to play, gathering Harry Kane's pass and arrowing a glorious shot into the bottom-left corner to secure an eighth successive league win.
- Hope for Middlesbrough -
Huth's unwitting intervention allowed Arsenal to prolong the momentum from their dogged 2-1 win over Manchester City in the FA Cup semi-finals on Sunday.
On a subdued night, and in front of many empty seats at the Emirates Stadium, Arsenal went closest to breaking the deadlock in the first half with an Alexis Sanchez shot that cannoned back off the crossbar.
Wenger threw on Danny Welbeck, Olivier Giroud and Aaron Ramsey in the second half, ditching the back-three system he has been using of late.
Victory looked likely to elude the hosts until five minutes from time when Nacho Monreal's shot took a huge deflection off Huth and looped over Kasper Schmeichel in the Leicester goal.
The win lifted Arsenal one place to sixth, four points behind fourth-place Manchester City and three points below fifth-place Manchester United.
Arsenal have played the same number of games as City and United, who meet in the Manchester derby on Thursday.
"Leicester were hard to break down, but we were patient and did not give away any chances," said Wenger, whose side visit Spurs in the north London derby this Sunday.
"Every win gives you a little more momentum.
"I don't have a preference for the Manchester derby. We don't have to look much at the others. We just have to look after ourselves. The target is clear for us."
The evening's other game also ended 1-0, Marten de Roon's eighth-minute goal seeing off bottom club Sunderland to give Middlesbrough a glimmer of hope in their battle for survival.
It was Boro's first win in 17 league games and took them to within six points of safety with four games to play, while Sunderland remain 12 points adrift of the survival threshold.