ATP World Tour Finals 2016 Results: Tuesday Tennis Scores and Updated Schedule

Novak Djokovic had to dig deep to book his spot in the semi-finals of the 2016 ATP World Tour Finals on Tuesday, beating Milos Raonic in two close sets in his second match of the group stages.

There was little to separate the two men, who served their way to two tiebreaks. Twice Djokovic held his nerve to finish the deal and make his final match of the group stage moot.

Earlier in the day, 23-year-old Dominic Thiem became the youngest player since 2009 to win a match at the World Tour Finals by beating Gael Monfils in three sets.

Here are Tuesday's results:

Winner	Score	Loser
Novak Djokovic	7-6 (6), 7-6 (5)	Milos Raonic
Dominic Thiem	6-3, 1-6, 6-4	Gael Monfils

The schedule for Wednesday:

Not before 2 p.m. GMT
Not before 8 p.m. GMT
Andy Murray	vs.	Kei Nishikori
Stan Wawrinka	vs.	Marin Cilic

Recap

As shared by TennisTV, the crowd at the O2 Arena were entertained before the match between Djokovic and Raonic even began, with a most unusual coin flip:

Djokovic had to save a few early break points, but apart from a scare in the third game, there was little either player could do about his opponent's serve in the first set. Raonic has been on fire in that department of late, largely negating Djokovic's sublime return skills.

Unsurprisingly, the tiebreak was a close affair, with Djokovic taking the early lead. A masterful lob gave him his first set point, and while the Canadian kept defending well, he eventually gave the set away with a double-fault.

Per Live Tennis, he couldn't have done much better:

"

That's just about the best set #Raonic could have played vs #Djokovic. And #Djokovic still won it. How does the Canadian recover from that? pic.twitter.com/IvobMlYIL9

— Live Tennis (@livetennis) November 15, 2016"

Their question was answered soon after, as Djokovic broke serve in the opening game of the second set. The Djoker appeared to be cruising and produced some of his best tennis, but somehow, Raonic managed to tie things up again in the fourth game with a fantastic backhand.

Meanwhile, Live Tennis noticed this odd challenge:

"

Is this:

(a) the worst Hawkeye challenge of 2016

(b) the worst Hawkeye challenge of all time

YOU DECIDE. pic.twitter.com/xkrsDSQimP

— Live Tennis (@livetennis) November 15, 2016"

The Serb grabbed another break in the fifth game, but once again Raonic fought back to tie things up at 4-4. Another tiebreak eventually followed, in which Raonic took an early lead, but the Djoker tied things up with a stunning volley. He finished things off with his second ace of the match.

Earlier in the day, Thiem grabbed his first-ever World Tour Finals win by beating Monfils in bizarre fashion. The win means his hopes of qualifying for the semi-finals are still alive.

The two split the first four games before Thiem switched gears, limiting errors and racing out to a 5-2 lead. As shared by TennisTV, analyst Rob Koenig was impressed:

The 23-year-old once again suffered a dip in form in the second set, however, and Monfils started doing tremendous damage with his serve. The Frenchman needed just 25 minutes to even the score and force a decider.

Monfils and Thiem kept things close in the final set, with the Frenchman playing more aggressively in the rallies. Here's a look at one of his best winners, courtesy of TennisTV:

But serving to stay in the match, Monfils fell apart completely. Three double-faults all but gifted Thiem a break chance, and an unforced error ended the contest in the Austrian's favour.

Per Stuart Fraser of MailOnline, Thiem knew he had some luck: “I think it was a close match. I had a much better stand, and then he was playing a good second set. The third set was very tight. Luckily he helped me in the last game of the match. Maybe I was the lucky one today.”

Justin Setterfield/Getty Images

According to Fraser, Thiem became the youngest man to win a match at the World Tour Finals since 2009.

Andy Murray and Kei Nishikori will battle for a spot in the semi-finals on Wednesday, while the loser of the match between Stan Wawrinka and Marin Cilic will see his hopes of surviving the group stages come to an early end.