Schalke coach Roberto di Matteo has stepped down after a disappointing season with a sixth-place finish in the Bundesliga.

Di Matteo says he is leaving because the "mortgage of an unsatisfactory second half of the season was too big," and he could not guarantee the success expected of the club for the future.

Di Matteo, who won the Champions League with Chelsea in 2012, took over at Schalke in October. He guided the club from 11th to third in the Bundesliga and nearly eliminated Real Madrid in the second round of the Champions League, winning 4-3 away.

But Schalke then took a slide in the standings and barely managed a slot in the Europa League.

Schalke did not name a successor. Di Matteo had another two seasons on his contract.