LONDON -- Jan Vertonghen has told ESPN FC that the 21-point gap to Manchester City does not represent Tottenham Hotspur's true strength.
The Belgium defender said Spurs, last season's runners-up in the Premier League, should be much closer to this term's runaway leaders but he backed the team to find an extra gear over Christmas and begin to close the gap in the second half of the campaign.
The 4-1 defeat at the Etihad Stadium last weekend leaves Spurs fighting for a spot in the top four, rather than the league title.
"There's a bit of frustration," Vertonghen said, when asked how it felt to see City so far ahead. "Not just for us -- for other teams as well probably. [The gap] reflects the strength of City but I don't think it reflects our [strength]. We could and should have been closer and I think we can reduce the gap definitely."
Spurs won six straight league matches between Dec. 14 and Jan. 14 last season, cutting Chelsea's lead from 10 points to six, and Vertonghen added: "I still think we're stronger than last year. We just have to get that run going, hopefully around Christmas.
"Obviously we lost 4-1 and City played very well but we can -- and will -- do a lot better in the next couple of games. We've got a lot of guys coming back from injuries -- there's still a couple out of course -- but I think we're looking very good at the moment."
However, Vertonghen said that Spurs were tighter defensively last season and said one of the things they have worked on during the seven-day break ahead of Saturday's trip to Burnley is defending after conceding three consecutive headed goals from corners in the matches against Watford, Stoke and City.
"It's the first time since August that we didn't have a midweek game so that helps us to focus on a couple of things in training and I feel like everyone is ready for Saturday," he said.
"[Defending corners] is a good thing to focus on when there's no midweek games. But it's not just corner kicks, it's a bit of shape, a bit of everything. It's good for us to get together, to know what we've achieved in the last couple of seasons. We still have the same group and we're still with each other. I see no reason not to get back on track during Christmas.
"A bit of luck is missing this year, but only Kyle Walker left us from that team [last season] and I see no reason we can't do the same again."
Spurs have missed Vertonghen's defensive partner Toby Alderweireld since he damaged his hamstring against Real Madrid on Nov. 1, losing three times in eight games without him and conceding 11 goals compared to seven in 10 games with him.
Vertonghen, however, refused to use his compatriot's absence as an excuse and said he hoped to continue playing with his former Ajax teammate for many years to come.
"Toby has been a great player for us over the last couple of seasons and so many players have now been injured. We have to cope with it. The other teams have had big injuries to big players. To challenge for the top four or the league, you need everyone in your squad and I think our squad has shown we can cope with it but Toby is a good player for us," Vertonghen said.
"Toby has shown his quality for us and I think I've played more than half my career games with him. I always enjoy playing with him and I hope I can we can do that for a long time coming."