Novak Djokovic has said that he played a "very bad match" during his quarter-final loss at the Cincinnati Masters.
The world number one lost in three sets to John Isner, who will now face Juan Martin del Potro in the last four.
"It's disappointing that I played this way. For me, it's very disappointing," ESPN quotes the top seed as saying.
"I just played a very bad match overall. Terrible match. From beginning to end, except the start of the second set, I was just a different player totally."
Cincinnati is the only Masters tournament that the Serbian is yet to win.
