In 2007 he trained at the Nick Bollettieri Tennis Academy in Florida and won four junior tournaments in the same year. He made his debut on the ATP World Tour in 2009 when he entered the Serbia Open with a wildcard . However, he lost to Marcel Granollers in the first round . In 2010 he won the Serbia Open in the quarterfinals against Novak Đoković , but failed in the semifinals to Sam Querrey . He made his Grand Slam debut in 2012 at the French Open , where he lost his opening game against Nicolas Devilder in three straight sets. In autumn 2017 he qualified as the final of the Paris Masters , in which he lost to Jack Sock in three sets after winning the starting set.