Mousa Dembele wants Tottenham to make amends for a miserable week by beating former club Fulham.
Having overcome Arsenal in the north London derby and trounced Inter Milan in the Europa League, Andre Villas-Boas' side were riding the crest of a wave little over a week ago.
However, a 3-2 defeat at Liverpool was followed by a 4-1 second leg defeat at Inter, where only away goals saved Tottenham's blushes after extra-time.
The lackadaisical performance at the San Siro was the most concerning aspect and leaves Spurs in need of a morale-boosting victory against Fulham.
``It was a bit embarrassing,'' Dembele told Press Association Sport. ``We thought it was going to be easier than this.
``We knew they were going to fight but it's a shame that we let them into the game.
``We had to work much harder but we are through and we have to take lessons from the game into the Fulham game.
``The thing is that if you go to a place with a 3-0 lead you take a different mentality. That was wrong.
``It didn't work, what we wanted to do. But we are through and that is okay.''
Tottenham's reward is a clash against Swiss champions Basle at the quarter-final stage of a competition Villas-Boas won as Porto manager two years ago.
Spurs are second favourites to win the competition behind Chelsea, who are also rivalling the north Londoners in the league.
Villas-Boas' side sit third with a two-point advantage over the Blues but their Champions League qualification is still far from secure, making Sunday's fixture against Dembele's former club particularly important.
``We lost against Liverpool, but I thought we played well,'' the Belgian said. ``Against Inter it was a different game to the one against Liverpool.
``This one against Inter we were not confident, but against Liverpool we were. At the weekend we have to be fully concentrated and go for the win.
``They have good players and against big teams they always play well. They are a good teams. They have some good players.''
Tottenham forward Gareth Bale returns to the squad after sitting out the trip to Inter Milan due to suspension.
Winger Aaron Lennon should return to the starting line-up after he came off the bench in Milan following his recovery from a hamstring injury. Former Fulham forward Clint Dempsey (calf) is also expected to be available.
Fulham manager Martin Jol admits he is still looking over his shoulder at the Barclays Premier League relegation scrap.
The Cottagers head to Jol's former club Tottenham lying in a healthy 10th position, but still only nine points above the drop zone.
Stoke, West Ham, Newcastle and Norwich all started the weekend level with Fulham on 33 points and the Dutchman knows any one of them could yet find themselves in trouble.
``We are in a good position but you have to look over your shoulder,'' said Jol.
``Four or five clubs are still with us there who could be dragged into a situation you won't like.
``We always say we would like to get 40 points as soon as possible and then, you never know. Last year we had 52 points and the year before we were in the top eight with 49, so hopefully we will get 40 and then a bit more.''
At White Hart Lane Jol will come up against Bale, the player he brought to Tottenham from Southampton as a 17-year-old in 2007.
Spurs are being tipped as potential title contenders over the next few seasons and Jol admits the in-form Welshman will be key to their chances
``They were 12 points ahead of Arsenal last season and at the end behind them so they were not consistent enough to contend for the title,'' he added.
``They are the same as they were the year before, but at some clubs you have the luck of having a player like Bale, making steps and getting better, so that is why they get better.''
Mahamadou Diarra should have been the player detailed to stop Bale, but Jol fears the former Real Madrid midfielder may not appear again this season due to a knee injury.
The 31-year-old Mali international has managed just eight appearances this term and will be out of contract in the summer.
``Diarra had an operation, came back, had another little operation but it's still painful,'' said Jol, who will have an unchanged squad for the game.
``We will go back to the surgeon and ask for different advice. I think it will be quite complicated without an operation to get him fit again. He will be out for the next couple of months.
``He was the main man last season, one of the most important players. It was a boost for us to get a player of his quality but you need him fit. But he has promised to get fit.
``If someone is not fit you have to assess the situation so hopefully in a couple of months we will sit down with him and make a decision.''