Tottenham's Champions League chase was refuelled by another late, late show as they beat Luton 2-1 - but they need to solve one big problem if they are to finish in the top five

After covering more than 14,000 air miles and scoring goals in Bangkok and Seoul, you could have forgiven Heung-min Son if weariness was creeping into his muscles as the clock ticked into the 86th minute.

Even so, he summoned the energy for one more run. Tottenham had been hammering away at Luton's depleted team for much of the second half, having gone behind early in the game and then equalised soon after half time.

But the visitors had been on the attack, searching for a winner when Son collected the ball, drove forward, released Timo Werner and kept on running. 

Werner found a change of pace and delivered a low cross from the left. Brennan Johnson nudged it back towards his captain and Son found the net with the help of a deflection.

It was his 160th Spurs goal, lifting him clear of Cliff Jones into fifth in the club's all-time list. Relief washed around the stadium. Victory felt crucial in the race for the Champions League after a heavy defeat at Fulham last time out.

They made hard work of it. Not for the first time this season. Luton were depleted, ravaged by injuries but determined. 

Ange Postecoglou applauded his players for their patience and refusal to give up. And there's always a chance with Son on the pitch.

'Outstanding,' said Spurs boss Ange Postecoglou. 'He's been a brilliant footballer for this club for a long time and hopefully for many years to come. He was really unlucky with a couple of chances and some good saves, but when we needed him he was there.

'I'm sure he feels tired. They are long trips and there's a time difference but he never looks for those clutches. He gets on with it. We try to look after him we can and the proof is there in what he produces.'

Luton went ahead inside three minutes, with a goal on the break created by former Spurs winger Andros Townsend, who won possession deep in his own half and carried the ball to the other end.

Townsend eased past Yves Bissouma and found Ross Barkley, who displayed the composure to resist the urge to go for goal and instead slid a pass to his left where Tahith Chong applied a precision finish.

Luton boss Rob Edwards punched the air. His team have scored in 18 successive league games and there were signs his game plan, tracking Tottenham's blur of movement with man-to-man marking, was working.

Still, there is great attacking quality in Postecoglou's team. They are relentless, and really should have equalised from one of two glorious chances created before the interval. Werner wriggled clear but pulled the first wide of the far post, dangerous and yet erratic as ever in front of goal.

Then Son skipped past Luton keeper Thomas Kaminiski only to see his shot strike the inside of one post, fizz square across the line, hit the other post and bounce out. Werner lashed the rebound at goal. 

Kabore made a block. Pape Matar Sarr took aim, beat Kaminski and found Teden Mengi on the line to clear.

It was a breathless pinball sequence. Luton survived and protected their lead until half time. Spurs trailed at the break.

Something of a bad habit. In seven home games since the turn of the year, they have not led at the interval. Some home fans booed their team off.

Johnson came on and made an impact, just as against Crystal Palace in the previous home game, forcing the equaliser, with a crisp one-two with Pedro Porro and low cross, turned into his own net by Kabore.

Kaminski made important saves, including one from Johnson, who thought he had scored as the ball spun along the line. 

Alfie Doughty hooked it clear and the goal line graphics showed one more revolution would have taken it in. There was only a millimetre or two to spare. 

Luton lost more players to injuries. 'We probably had our last 10 fit senior outfield players on at the end,' said boss Edwards. They even had a go at winning it. Jordan Clark forced a fine save from Guglielmo Vicario.

And it was Son who settled the game. 'Massive for us,' said Tottenham's captain. 'We don't want it to always end like this. It could be nicer to have three points earlier.

'I was really frustrated but I wanted to stay calm and not show too much emotion.'

Heartbreak for Luton, who slip into the relegation zone on goal difference. 'It hurts,' said Edwards. 'I feel sick.'