Wolfsburg must attack Gent in the second leg of their Champions League last-16 tie, despite heading into Tuesday's match at the Volkswagen Arena with a 3-2 lead, says Koen Casteels.
Dieter Hecking's side surged three goals ahead in the opening encounter at the Ghelamco Arena on February 17 and looked set for a simple route into the quarter-finals when Max Kruse added to Julian Draxler's double in the 60th minute.
But the Bundesliga side failed to hold onto their advantage, conceding goals to Sven Kums and Kalifa Coulibaly in the final 10 minutes to set up a tense return match.
Casteels was in goal for Wolfsburg and looks set to be so once more on Tuesday, with Diego Benaglio missing their last six matches due to a rib injury.
The Belgian believes Gent's late showing proves they must not be underestimated, urging an attacking display to ensure progression.
"We must approach this one as a completely new game. We can't just afford to defend our advantage, but rather play attacking football and get at least one goal," said Casteels.
"In Gent we saw that they can play football and that we should not underestimate them. They will be doing all in their power to turn the tie around and progress to the next round."
Wolfsburg head into the game on the back of a 2-1 victory over Borussia Monchengladbach in the Bundesliga on Saturday.
Josuha Guilavogui believes the triumph will hold Hecking's side in good stead as they look to secure a place in the last eight for the first time in their history.
"[Winning] against a team like Borussia Monchengladbach, who are one of the best sides in the Bundesliga, then that is very important for our self-confidence ahead of Tuesday night's game," he said.
"It's quite simple: we have to win the game in order to take our quarter-final place. We will do everything necessary to ensure that's the case."
Wolfsburg have suffered one defeat at home in the Champions League - a 3-1 loss to Manchester United in 2009 - but Gent, enjoying an impressive debut campaign, picked up a 2-1 win away at Lyon in the group stage.
Furthermore, the Belgian champions have been victorious in both of their two previous visits to Germany - overcoming Eintracht Frankfurt 1-0 in the 1991-92 UEFA Cup and Werder Bremen 3-2 in the 2001 Intertoto Cup.
However, with just one win from three matches since their first-leg defeat - a run which includes a crushing 5-2 loss at KV Oostende - their confidence may be knocked.
Wolfsburg remain without Bas Dost (foot), Sebastian Jung (knee) and Paul Seguin (ankle). Gent will be unable to call upon Thomas Matton (foot), while Brecht Dejaegere, Lasse Nielsen (both hamstring) and Danijel Milicevic (ankle) are doubts.
Key Opta stats:
- Wolfsburg have won their last three Champions League games, their best ever run in the competition.
- Gent's last six Champions League games have all been decided by a one-goal margin (W3 L3).
- Gent have so far scored in each and every single Champions League game this season (7 games).
- Only one of Wolfsburg's 13 games in the Champions League has ended in a draw, that was against Besiktas in October 2009 (0-0).
- Gent's Kalifa Coulibaly has scored two goals in his last three Champions League appearances, all as substitute.