Monfils defeated Gasquet 6-4, 6-4 in Sunday's final of the Open Sud de France for his second win in Montpellier, France. He won the title there in 2010 and was runner-up in 2012
Monfils lost to Gasquet in the second round in 2013 when Gasquet went on to win the event.
The Monfils win Sunday was his fifth ATP title but first since October 2011. He'd lost five straight finals appearances since then. The championship lifts him from 30th to No. 23 in the rankings.
With Gasquet seeing a net loss of rankings points this week, he is just 65 points ahead of Tsonga.
Other ATP winners last week were Fabio Fognini, whose championship at the Royal Guard Open Chile moves him to a career best No. 14 ranking, and Marin Cilic, whose repeat win at the PBZ Zagreb Indoors keeps him at No. 37. Cilic owns 10 ATP titles, four of them coming at the Zagreb Indoors.
The ATP contests three tournaments this week, including the ABN AMRO World Tennis Tournament, which features defending champion and No. 4-ranked Juan Martin del Potro and four other Top 10 players. The others are No. 6 Andy Murray and seventh-ranked Tomas Berdych, along with Gasquet and Tsonga, who could meet in the semifinals.
No. 5-ranked David Ferrer, another defending champion, leads the field at the Copa Claro in Argentina. Kei Nishikori and Felecia no Lopez, who played in the finals of last year's U.S. National Indoor Tennis Championships in Memphis, are seeded 1-2 in the event this year. Nishikori was a 6-2, 6-3 winner in the title match last year.
The ATP Top 10, listing player's name, home country and rankings points:
1. Rafael Nadal, Spain, 14,330
2. Novak Djokovic, Serbia, 10,580
3. Stanislas Wawrinka, Switzerland, 5,710
4. Juan Martin del Potro, Argentina, 5,370
5. David Ferrer, Spain, 5,280
6. Andy Murray, Great Britain, 4,795
7. Tomas Berdych, Czech Republic, 4,540
8. Roger Federer, Switzerland, 4,355
9. Richard Gasquet, France, 2,950
10. Jo-Wilfried Tsonga, France, 2,885