Tottenham Hotspur's Son Heung-min celebrates scoring his side's third goal of the game during the Champions League Group B match against Red Star on Tuesday. Photo: Nick Potts/PA via AP

LONDON – After a demoralising and increasingly puzzling start to the season, Tottenham Hotspur finally clicked into gear with a 5-0 hammering of Red Star Belgrade which they hope will restore confidence ahead of a Sunday's daunting trip to Liverpool.

Two goals apiece from Harry Kane and Son Heung-min and one for Erik Lamela earned Tottenham a first win in this season's Champions League and put them second in Group B.

It was only their fourth win in 13 games in all competitions this season -- a run which included a 7-2 home hammering by Bayern Munich in the previous round of Champions League matches, followed by a 3-0 defeat at Brighton and Hove Albion.

The north London club have looked a pale shadow of the side that reached last season's Champions League final and claimed a fourth successive top-four spot in the Premier League.

One big win against a Red Star side who were outclassed will not erase the doubts, but it was a timely boost ahead of Sunday's trip to Anfield to face a rampant Liverpool side they lost to in the Champions League final in Madrid in June.

Tottenham's Harry Kane scores his side's fifth goal on Tuesday. Photo: AP Photo/Ian Walton

“It was important to get the first goal, and then we could manage the game,” Lamela, who added two assists to his well-taken goal on his 200th appearance for the club, said.

“It's a very positive night. We are much better in the group and our confidence is much better after winning the game 5-0.

“I am more than happy that we won, we needed this win so much and now we have to enjoy tonight.”

With Christian Eriksen, Giovani Lo Celso and last season's hero Lucas Moura all on the bench and Danny Rose and Toby Alderweireld not even in the squad, there is no doubting the quality in Tottenham's squad.

But for whatever reason, the team has looked stale this season, although Kane has been one of the few exceptions with nine goals in all competitions.

“The most important thing was the win,” Kane said. “To win 5-0 was exactly what we needed. We've got a long way to go.

“Hopefully we can build on this. Liverpool is a tough game coming up, obviously they have started the season fantastic, but hopefully we can win that game.”

Tottenham's Harry Kane applauds fans at the end of the Champions League, group B, soccer match between Tottenham and Red Star Belgrade. Photo: AP Photo/Ian Walton

Compared to last season when Tottenham managed only one point from their first three Champions League games, Pochettino's side are in decent shape this time, with four points and in second spot behind Bayern Munich.

Pochettino said there was still a lot of hard work to do though with a trip to Belgrade in two weeks and also an away clash in Munich and a home game against Olympiakos.

“It's all open. We are better position than last season,” Pochettino told reporters. “The most important thing is to stay calm, don't make a drama. Smile at the problems, be positive and hope that continues for the next games.”