- Thiem beats Monfils 6-3 1-6 6-4
- The Austrian, 23, is the youngest player at the event
- Novak Djokovic will qualify for the semis with a win later Tuesday
London (CNN)The tennis season is long, very long, lasting 11 months in the men's game.
It comes as little surprise then that come November, fatigue and injuries -- so often correlated -- surface, even for the best in the game. In fact, the elite may be more prone to ill health towards the end of the campaign due to the sheer number of matches they play.
When the groups were announced at the World Tour Finals, three particularly banged-up players fell in group Ivan Lendl: Gael Monfils, Dominic Thiem and Milos Raonic.
Monfils missed the Paris Masters at home with a rib complaint, Raonic was forced to pull out of the semifinals in the French capital earlier this month with a thigh injury and Thiem has contested a staggering 27 tournaments in 2016, more than anyone ranked inside the top 20.
The fourth member, Novak Djokovic, isn't in ideal shape, either.
As Thiem met Monfils Tuesday afternoon in London, the physical exertions of the season were plain to see but one had to win and it was the young Austrian Thiem who outlasted the French showman 6-3 1-6 6-4 in a battle of tournament debutantes.
He kept alive his chances of advancing to the semifinals: Thiem improved to 1-1, with Monfils dropping to 0-2. Monfils will officially be eliminated if Djokovic -- a 6-7 6-0 6-2 winner over Thiem on Sunday -- defeats Raonic (1-0) later Tuesday.
"I think it was a decent first match," Thiem, 23, told reporters. "Also today I had a good start. I tried to avoid the mistake I did in the first match -- to drop a little bit.
"I was trying to stay tough in the third set."
The normally fleet-footed Monfils was clearly in distress chasing balls and landed awkwardly trying to retrieve a smash while Thiem's distress manifested itself in some head -scratching misses. On back-to-back points late in the third set, Thiem nearly ballooned a forehand into the crowd and sent a routine looking backhand volley yards wide and long.
Rallies were short, leading to the first two sets being completed in 51 minutes. Monfils, unusually for him, regularly served and volleyed.
Asked about his fitness level, Monfils, 30, said: "Not my best."
But the duo also lived up to their crowd-pleasing reputations. Thiem, a shotmaker with bulldozing penetration on both the forehand and backhand, ripped winners. Monfils swiveled to hit a forehand down the line and casually produced a backhand passing shot winner -- when his point of contact with the ball seemed to be behind him.
Both finished with more winners than unforced errors.
Unfortunately for Monfils, he struck three double faults in the final game -- all on the deuce side -- to account for the lone break of the third.
When Monfils erred on the final point, Thiem became the first Austrian to win a match at the year-end championships since Thomas Muster -- a left-hander who had the majority of his success on clay -- in 1996. He continued to produce, too, in deciding third or fifth sets, rising to 21-3 in 2016.
He defended his schedule and didn't rule out playing as many matches -- he's up to 81 now -- next year.
"If I would have played less, I wouldn't be here at the Finals," said Thiem, who earned his place in London after Rafael Nadal cut his season short to heal a wrist injury. "This was one of the reasons why I'm here, because I was playing a lot.
"Maybe I will play a little less, but also maybe not."
He certainly wouldn't mind playing three more matches -- which would see him make the final -- this year.