Alex de Minaur has bowed out of his maiden ATP Finals in Turin with a third loss and nothing to show for his typically valiant efforts, except a seemingly painful reminder of his troublesome hip injury.

De Minaur, needing a win to keep alive his already wafer-thin hopes of making the semifinals of the season-ending men's championship, ended up wincing in obvious discomfort near the end of his 5-7, 6-4, 6-3 defeat by Taylor Fritz at the Inalpi Arena.

Any recurrence of the left-hip problem that first derailed him at Wimbledon in July is of concern with the looming prospect of de Minaur being drafted in to Lleyton Hewitt's Australia team at the Davis Cup Finals in Malaga next week.

His defeat followed losses to Jannik Sinner and Daniil Medvedev on his maiden appearance at the Finals earlier this week, but as ever "Demon" didn't succumb without a real battle on Thursday, local time, despite an apparent flare-up of the injury that's dogged his second half of a terrific breakthrough season.

Still fighting furiously at the end of the second set, there was even a chance de Minaur could win in straight sets after a terrific attacking performance and still have a long-odds shot at making the semi-finals.

But having dropped just point on serve in the rest of the second stanza, one absent-minded game when serving to stay in the set was then enough to allow Fritz to level at one-set apiece and ensure de Minaur was eliminated.

The knowledge of his exit may have knocked the wind out of de Minaur's sails as he was broken in the decider to go 3-1 down and then grimaced in clear pain after stretching to his right and trying to shift back to his left a couple of games later.

Still, though, the indefatigable 25-year-old managed to conjure up the point of the match, with an incredible bit of retrieving and a running forehand lob that left Fritz almost incredulous.

The best of de Minaur's 27 winners still wasn't enough to stop the US Open finalist Fritz running out the winner in two hours six minutes, a win that guaranteed world No.1 Sinner was the first player to advance to the weekend's semi-finals.

Medvedev has to beat Sinner later on Thursday in straight sets to advance in the tournament. If the Italian wins or takes just a set off the Russian, Fritz will qualify.

AAP