Jordan Thompson has beaten world number eight Casper Ruud yet again at the Paris Masters, while compatriot Alex de Minaur gave himself every chance of reaching the season-ending ATP Finals.

It was a good day for the Australian contingent in Paris, with Alexei Popyrin also advancing, although Chris O'Connell lost to Karen Khachanov.

Thompson scored the biggest scalp, taking down Ruud for the third time this year and moving into the third round with a 7-6(7/3), 3-6, 6-4 win in two-and-a-half hours at the indoor event.

The 28th-ranked Sydneysider was broken in just his second service game of the match and went behind 5-2 in the opening set, but dropped just two points as he stormed back to 5-5.

He forced a tie break and won it 7-3 after just over an hour, before Ruud hit back and broke twice to take the second set 6-3.

Thompson broke in the third game of the decider, but Ruud immediately cancelled it out to make it 2-2. The pair traded service holds to 4-4, but Thompson broke to love and held his nerve from 15-30 in the next game, winning a 27-shot rally to claim his first match point.

It means Thompson has now beaten three-time major finalist Ruud three times this year, adding to victories in the Los Cabos final and in Tokyo last month.

Ruud has won just one of his past seven matches.

Meanwhile, de Minaur's hopes of reaching the season-ending ATP Finals were boosted by a first-round victory in Paris, as his biggest rival fell short.

Both de Minaur and Russian Andrey Rublev took to the court at the indoor Paris Masters, with de Minaur progressing to the second round, while Rublev lost to 29th-ranked Argentinian Francisco Cerundolo.

De Minaur comfortably beat Cerundolo's countryman, Mariano Navone, 7-5, 6-1 to move into a second-round clash with lucky loser Miomir Kecmanović to stay in touch with Rublev.

Rublev is currently occupying the last place in the race for the eight-man ATP Finals, with de Minaur hot on his heels in ninth.

De Minaur will leapfrog the Russian — vying for his fifth straight appearance at the showpiece tournament in Turin, Italy — with a quarterfinal berth in France.