The 31-year-old, who arrived in Qatar after a four-month break due to a knee injury, dominated throughout.
He broke Rublev's serve in the fourth game of each set and barely look troubled by the Russian, who has been so impressive all week but could not cope with the power of Monfils. The world number 46 took the first set in just 23 minutes, and in the second was able to save two break points in the fifth game after establishing a 3-1 lead - the only time the Frenchman's serve was put under pressure. Monfils needed only one championship point to secure the match after exactly an hour on court. Rublev looked crestfallen afterwards but has the consolation that he will be seeded at the forthcoming Australian Open.