Jerome Boateng says 2018 wasn't a great year for him. Photo: Michael Dalder/Reuters

BERLIN  Germany and Bayern Munich defender Jerome Boateng has admitted to a difficult year 2018 but insists he isn't finished yet.

Boateng, in an Instagram post Sunday, named the group stage exit at the World Cup in Russia "one of the most disappointing experiences of my career" but added "I have gotten over it and learnt from it."

Bayern's latest Champions League exit and German cup final defeat were other disappointments for the 30-year-old who in summer was briefly linked with a move to Paris Saint-Germain.

"2018 is ending and I must admit I am happy about it. It was a very difficult year for me personally, I will probably never remember it well or even fondly. I was far below my sporting expectations," he said.

Boateng has also been hampered by injuries but he vowed to fight back in 2019.

"I use the criticism and doubts which have arisen as a motivation because I am not finished yet," he said.

"I have learnt a lot. I feel better physically in the past weeks and am on my way back to top form ... We want to be in all competitions until the end and fight for titles."