his coach Jan de Witt, who was later replaced by Mikael Tillström. His last tournament of the year was the Paris Masters. After leading by one set and 4–0 he was knocked out in the first round by compatriot Benoît Paire. He said after the match he got disturbed when the crowd started to whistle at his opponent. In his own words, Monfils defined 2015 as a "year of regrets" where he "regressed, wasted a year because of certain choices". 2016: US Open semifinals, first ATP 500 title, World No. 6 Monfils started the 2016 season by entering the 2016 Australian Open where he was seeded twenty-third, Monfils took advantage of a draw which opened up in his section to reach the singles quarterfinals of the Australian Open for the first time. There, he lost to the thirteenth seed Milos Raonic in four sets. His good form continued going into the Rotterdam Open, where he reached his first final of 2016, defeating Ernests Gulbis, Borna Ćorić, Alexander Zverev and Philipp Kohlschreiber en route before losing to Martin Kližan in three sets. In March, Monfils reached the quarterfinals of two ATP World Tour Masters 1000 tournaments – Indian Wells and Miami, losing to Raonic and Kei Nishikori respectively. Monfils then reached a third career ATP World Tour Masters 1000 final and second final of 2016 in Monte Carlo, that of which saw him defeat countryman and world No. 9 Jo-Wilfried Tsonga in the semifinals en route, before ultimately losing in the final to the eight-time Monte Carlo Masters champion Rafael Nadal in three sets. Monfils then looked to again replicate this form at the next two clay-court ATP World Tour Masters 1000 tournaments – the 2016 Madrid Masters and the 2016 Rome Masters. He caught a viral infection during his stay in Madrid and, as a result, ended up losing in the second round to Pablo Cuevas. This viral infection ultimately saw Monfils withdraw from the 2016 French Open as well. Prior to that however, he lost in the first round of the 2016 Rome Masters to Thomaz Bellucci. Still feeling sick, Monfils wouldn't play again until Wimbledon. In an attempt to recover, he lost his first-round match with compatriot Jérémy Chardy in five sets. Monfils earned his first ever ATP World Tour 500 Series singles title in July, in the second week after Wimbledon, defeating Croatian Ivo Karlović in the