Harry Redknapp's side, who host West Bromwich Albion on Tuesday, wasted a chance to close the gap on leaders Manchester City and second placed Manchester United as Swansea snatched a late equaliser to draw 1-1 at the Liberty Stadium on Saturday.
Van der Vaart had given Spurs the lead but Scott Sinclair's strike six minutes from time meant a frustrating journey home from south Wales.
Tottenham would have been only four points behind City and United if they had held on and Dutch star van der Vaart knows his side must cut out the lapses in concentration that sometimes afflict them.
"It was disappointing to lose a goal just before the end of the game. The fact we're disappointed is also a good sign," Van der Vaart said.
"Perhaps a couple of years ago Tottenham would be happy with a draw on this occasion but we know we can do more.
"It's been a great first half of the season though and we have lots to look forward to."
Despite Tottenham's occasional frailties, United boss Sir Alex Ferguson believes they are playing the best football in the Premier League this season.
And, while third placed Spurs would be more than happy to finish the season back in the Champions League after missing out last term, City's shock defeat at Sunderland on New Year's Day means a surprise title challenge is still possible.
A win over Albion could lift Spurs to within three points of City and United if the top two slip up again against Liverpool and Newcastle respectively.
But Redknapp's hopes of moving closer to the top would be dented if England midfielder Scott Parker is unable to feature on Tuesday.
Parker suffered a knee injury in the first half of the 1-1 draw at the Liberty Stadium and he was eventually substituted with 19 minutes remaining.
The injury is still being assessed but Parker is already a doubt for Albion's visit to north London.
"It's too early to say (how bad it is). He took a bang on the knee in the first half and you could see how he was struggling but he carried on with it," Redknapp said.
"He has made a massive difference since he came in, we haven't lost many when he has played.
"I think only once he has been on the losing team, he has been that important."
In contrast to Tottenham's lofty ambitions, Albion travel to north London knowing any kind of positive result will be another step towards survival.
Roy Hodgson's side are already seven points clear of the relegation zone, but Sunday's 1-0 home defeat against Everton was a major disappointment.
And Hodgson wants backing from the board in the January transfer window to ensure Albion don't get sucked into the relegation dogfight.
"If we are going to have a good season, we need some help," he said.
"I'd like to think we have got to the stage where the type of players that would help us would cost money and demand high wages.
"I'm not certain at the moment that is the way we are looking to go forward.
"I'm not interested in bringing bodies or extra names into the club unless I am sure they are better than what we have got."
Source: AFP
Source: AFP