Wolfsburg have headed into half time level with Schalke 04 after a goalless first 45 minutes at the Volkswagen Arena.
The two German sides have put on an energetic display but, despite the end-to-end action, neither side has been able to break the deadlock.
The hosts will argue that Roberto Di Matteo's side should be down to 10 men, after Sead Kolasinac wiped out midfielder Vieirinha in what was deemed a dangerous tackle to only warrant a yellow card.
Vieirinha had one of the home side's best chances to take the lead when a looped through-ball was hit on the volley by the Portuguese winger, but his shot nearly turned into an assist, with Ivan Perisic unable to keep his header down.
Perisic's neat footwork on the byline helped him sneak a shot away, only for Ralf Fahrmann to deny the Croatian and then stop Kevin De Bruyne's follow-up attempt.
Schalke had shouts for a penalty turned down as Klaas-Jan Huntelaar was muscled over inside the box by Naldo, only for the referee to decide that it was a fair challenge.
