The Lions conceded a two-goal lead against the Royal Blues at the Veltins Arena to settle for a 2-2 draw.
"We played really well in the first hour or so," he told reporters. "Our shape was good, we defended well as a team and looked threatening going forward.
"After we scored our second, Schalke really upped the pressure and anything could have happened in the closing stages."
Bayer are currently third in the Bundesliga with 50 points from 29 matches.