He followed this up with another victory over Olivier Patience in the second round to reach the quarterfinals where he lost to fellow wildcard and junior and eventual finalist Richard Gasquet in straight sets.

[citation needed] In the last three months, he went 15–8, highlighted by his first ATP clay title at the Idea Prokom Open in Sopot, defeating Florian Mayer in the final.

Monfils had a good run in Poertschach as a warm-up for the French Open, but lost in the final against Juan Mónaco of Argentina in straight sets.

At the 2009 Australian Open, Monfils lost to fellow Frenchman Gilles Simon in the fourth round, retiring due to a wrist injury.

[28] He then played a much-anticipated fourth-round match against Andy Roddick, who made 28 unforced errors en route to losing to Monfils in straight sets.

Despite suffering from jetlag, Monfils also made the quarterfinals at the Malaysian Open, held in Kuala Lumpur, where he was beaten in straight sets by Nikolay Davydenko.

[32] He then played in the ABN AMRO World Tennis Tournament in Rotterdam, where he fell in the quarterfinals to the eventual runner-up, Russian Mikhail Youzhny in three sets.

Monfils was seeded twelfth at the 2010 Paris Masters and successfully reached the final for the second consecutive year, this time also scoring three Top 10 wins (Fernando Verdasco in third round, Andy Murray in the quarterfinals and Roger Federer in the semifinals) en route to doing so.

[41] At the Legg Mason Tennis Classic in Washington, D.C., he reached the finals with victories over Ryan Sweeting, Dmitry Tursunov, Janko Tipsarević and John Isner.

[54] For his season debut on clay at the 2015 Monte Carlo Masters, he successively beat Andrey Kuznetsov, Roger Federer and Grigor Dimitrov but lost to Tomáš Berdych in the semifinals.

[62] 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.

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.

The following week, Monfils reached the semifinals of the 2016 Canadian Masters after dispatching 2016 Wimbledon singles finalist Milos Raonic in the quarterfinals, to set up a match against world No.

In the second week of August, since Richard Gasquet withdrew from the 2016 Olympics tennis tournament because of an injury to his back, Monfils would pair up with Jo-Wilfried Tsonga in the men's doubles draw.

[63] In the men's singles draw of the same tournament, Monfils reached the quarterfinals and lost to eventual bronze medalist Kei Nishikori, despite having 3 match point chances in the deciding set.

In late August, Monfils entered the 2016 US Open seeded tenth and reached the semifinals without dropping a set, defeating prominent past and present players on the tour Gilles Müller, Jan Šátral, Nicolás Almagro, Marcos Baghdatis and Lucas Pouille en route.

Monfils then entered the Shanghai Masters seeded sixth and received a bye into the second round, where he defeated Kevin Anderson in straight sets.

Appearing in the 2018 edition of the tournament as an unseeded wildcard, he advanced to final via walkover after top seed Dominic Thiem had to withdraw from their match in the semifinals because of illness.

In round one, Monfils completed a significant comeback to beat Horacio Zeballos, saving one match point in the process with a booming forehand.

Monfils won the eighth ATP Tour singles title of his career at the Rotterdam Open, defeating Stan Wawrinka in a three-set final.

One of the highlights of his year was when he reached the quarterfinals of the US Open as the 13th seed after battling past Denis Shapovalov in the third round and dispatching Pablo Andújar only losing a maximum of 2 games in each set.

Monfils won the ninth ATP Tour singles title of his career at the Open Sud de France, defeating Vasek Pospisil in straight sets 7–5, 6–3.

[71] In the next Masters at the 2021 Western & Southern Open in Cincinnati, he defeated Alex De Minaur to reach the last 16, and the 500th win in his career on the ATP tour marking an important milestone.

[77] He reached the quarterfinals at the Canadian Open defeating Christopher Eubanks, fourth seed Stefanos Tsitsipas and lucky loser Aleksandar Vukic.

[81] He reached his first semifinal of the season as a wildcard, at the Qatar Open in Doha, defeating Botic van de Zandschulp, Zhizhen Zhang and compatriot and third seed Ugo Humbert becoming the oldest semifinalist at the tournament at 37 years old.

[88][89][90] At 38-years-old, Monfils recorded a straight sets win over ninth seed Jan-Lennard Struff, becoming the oldest quarterfinalist at the 2025 ASB Classic in Auckland since Roger Taylor in 1970.

[95] Monfils defeated qualifier Zizou Bergs, becoming the oldest champion on the ATP Tour and also the oldest-ever men's singles title winner since 43-years-old Ken Rosewall in 1977 in Hong Kong.

[96][97] Monfils became the only player ever not to face a break point in a five-set match at a Slam (since records started in 1991) when he won against compatriot and 30th seed Giovanni Mpetshi Perricard in the first round at the 2025 Australian Open.

[109] In February 2025, Monfils confirmed that he would quit tennis if he sufferedan injury setback in the course of the 2025 season[110], just after he became the oldest player to win an ATP Tour title in Auckland at age 38 years and four months old[111].