Novak Djokovic was keen to look ahead after suffering a shock defeat to fellow Serb Viktor Troicki in the second round of the Croatia Open.
Djokovic was broken six times by his Serbian compatriot
Troicki, the world number 176, recorded only his second ATP match win - against the world number three.
But after losing 6-2 4-6 5-7, Djokovic said: "Viktor played a good match and he deserved to win.
"Of course I'm disappointed but you have to turn the page and look ahead after such a loss."
The defeat ends Djokovic's European clay-court season and the 20-year-old will now begin his preparations for the US Open, beginning with the Montreal Masters on 6 August.
Troicki's only previous match against a top-10 player came in the second round in Tokyo last year when he lost in two tiebreaks to Roger Federer.
The 21-year-old will now face Argentine Carlos Berlocq in the quarter-finals of the clay-court tournament in Umag.
"Novak and I have known each other since we were eight," said Troicki.
"I played against him many times, but I only remember beating him once in the under-10s.
"I think that my game is at a good level right now, I'm trying to give my best and I hope that I'll be able to reach the top 50 at some point."