Outscoring the opposition was the mentality at Tottenham last season but now the focus is on keeping out goals at the other end of the pitch.

Tuesday's 1-0 win against Villarreal in Spurs' Champions League opener was the fourth clean sheet they had kept in five games so far this season under Thomas Frank.

In contrast, they had kept just one at the same stage of last season, when the more attack-minded Ange Postecoglou was in charge.

"We talked a lot about 'clean sheet mentality' this year because we conceded a lot last year," Tottenham midfielder Lucas Bergvall told Amazon Prime.

"They [Villarreal] did not have a shot on target, so we did a really good job."

Defender Micky van de Ven added: "I think we are a difficult team to play against, for sure. Structure-wise we are standing really good and we all know what to do, so we're a difficult team to beat."

The style of Frank's Tottenham side against Villarreal was in stark contrast to the swashbuckling football played under Postecoglou.

They were much more cautious, even after being gifted a fourth-minute opener thanks to a calamitous mistake by Villarreal goalkeeper Luiz Junior.

But their defence was excellent, with Van de Ven in particularly halting most of Villarreal's attacks.

Even though the visitors had 10 shots, Guglielmo Vicario didn't have a save to make throughout.

The price for that level of pragmatism was that Tottenham themselves only had one shot on target - very little for the home fans to get excited about.

"We defended really well and gave little away throughout the game against a really good Villarreal side," Frank said.

"I think offensively we didn't hit the highest level. There was definitely a spell second half where we decided let's give it to the Villarreal guys and then we'll sprint back, that's a very good fun thing.

"It was a very even game that we just edged."

Tottenham have conceded just the one goal so far this season - in the 1-0 loss to Bournemouth.

That is a big improvement on how they started the previous campaign, when they conceded five in their first five games.

In the Premier League they have kept three clean sheets already - meaning they are just two away from equalling their total for the whole of last season.

The more solid platform is potentially coming at a cost, however, with their one shot on target against Villarreal the second time in their last three games they had managed so few efforts on goal.

Frank knows this is an area that has to improve.

"We have a very good foundation to stand on in terms of our defensive organisation and I think it's good and we gave little away," he said.

"This is the Champions League against a good team. Also, I knew we took a step forward against West Ham, offensively is the area we need to get better."