Constant Lestienne

The Serb broke his Russian opponent twice as he cruised to the opening set, and though Safiullin took the 21-time grand slam champion to a tie-break in the second, Djokovic's class showed as he won the tie-break 7-3 to ensure his place in Sunday's decider.

It was far from plain sailing for Djokovic, who conceded the tension in the second set was hard to handle.

Djokovic said: "I think it was a very competitive match, especially in the second set.

"I must say I was quite emotional on the court today in the second set, there was a lot of tension, and that was also due to his aggressive style of tennis. Big serves, and when he has time, he's so solid from the forehand and backhand corner.

"I knew that I had to stay very strong, and that he was definitely going to raise his level in the second set, which happened. I was serving for the match and played a couple of loose points, but credit to him for fighting back. It was an enjoyable evening on the court for sure."

Marin Cilic secured his spot as Djokovic's final opponent with a comfortable straight sets triumph over Constant Lestienne.

The Croatian second seed served 14 aces as he eased to victory in under two hours, winning 11 out of his 12 first-serve points en route to a 7-5 6-3 win.

Holger Rune is into the Sofia Open final after Jannik Sinner was forced to retire through injury with the Dane leading 5-7 6-4 5-2.

Sinner won the opening set but lost the second, and with Rune just one game away from winning the match, the top seed chose to retire with ankle pain, putting an end to his hopes of winning three straight titles in Sofia.

Rune will face Marc-Andrea Huesler in the final, after the world number 95 upset fourth seed Lorenzo Musetti.

The first set went to a tie-break as neither could find a break of serve, though Musetti found two in the tie-break to help him to a 5-1 lead.

However, the Italian surrendered the next six points as Huesler pulled off an incredible comeback to take the first set.

The second set was another tight affair as both held serve after serve, but Huesler finally found a crucial break to prevail 7-6 (7-5) 7-5.

The number two seed got off to a rocky start, finding himself 5-2 down in the first set before dramatically turning the tide, winning five straight games.

Rublev's first serve percentage improved from 49 to 58 in the second set as he stepped up his game against his Serbian opponent.

"Filip is one of my good friends, and we always have tough battles," Rublev said after his win. "So, today I was going on court thinking that it was going to be a really tough match, and when he started the way he did, I didn't know what to do because he was playing so good.

"Somehow I calmed myself and said 'OK, restart at the bottom and raise my level', and I started to play much, much better. I was able to turn the match around and finish the match in a good way."

He will face Alejandro Davidovich Fokina in the second round after the Spaniard took just 52 minutes to beat Malek Jaziri 6-2 6-0, converting all five of his break points as he strolled to victory.

Seventh seed Alexander Zverev had to come from behind to beat Jiri Lehecka 4-6 6-3 6-4, while Tallon Griekspoor set up a second-round clash with top seed Novak Djokovic after the Dutchman beat Constant Lestienne 6-4 3-6 6-2.

The other semi-final will be an all-French battle between Richard Gasquet and Constant Lestienne, who both came from a set down to see off David Goffin and Laslo Djere respectively.

At the Auckland Open, second-seed Briton Cameron Norrie beat American Marcos Giron 6-1 6-7 (5-7) 6-2 to set up a last-four clash with another player from the USA, Jenson Brooksby, who edged past France's Quentin Halys 7-6 (7-3) 7-6 (7-2).

The other semi-final will be an all-French battle between Richard Gasquet and Constant Lestienne, who both came from a set down to see off David Goffin and Laslo Djere respectively.

At the Auckland Open, second-seed Briton Cameron Norrie beat American Marcos Giron 6-1 6-7 (5-7) 6-2 to set up a last-four clash with another player from the USA, Jenson Brooksby, who edged past France's Quentin Halys 7-6 (7-3) 7-6 (7-2).

The other semi-final will be an all-French battle between Richard Gasquet and Constant Lestienne, who both came from a set down to see off David Goffin and Laslo Djere respectively.

At the Auckland Open, second-seed Briton Cameron Norrie beat American Marcos Giron 6-1 6-7 (5-7) 6-2 to set up a last-four clash with another player from the USA, Jenson Brooksby, who edged past France's Quentin Halys 7-6 (7-3) 7-6 (7-2).

The other semi-final will be an all-French battle between Richard Gasquet and Constant Lestienne, who both came from a set down to see off David Goffin and Laslo Djere respectively.

Thanasi Kokkinakis is on a roll again at the Adelaide International 2 where the hometown hero and defending champion marched into the semi-finals on just two hours' sleep.

The Australian wildcard saw off Serbian sixth seed Miomir Kecmanovic 6-3 6-7 (4-7) 6-1 on Thursday to set up a semi-final against Spain's Roberto Bautista Agut.

Kokkinakis had a stellar run to the title at this tournament 12 months ago, beating John Isner and Marin Cilic before knocking over Frenchman Arthur Rinderknech in the final.

A first-round exit followed at the Australian Open, although he memorably won the doubles title with Nick Kyrgios. Kokkinakis struggled for the rest of the year, with his ranking currently at 110.

Kokkinakis said after his latest win: "I didn't sleep much last night. I reckon I got to sleep at about five and maybe slept for a couple of hours.

"I just couldn't sleep for whatever reason, so I was trying to conserve energy. I didn't want to use it too much. I had a couple of Monsters [energy drinks] before I started and tried to get going.

"When I'm serving well my whole game follows, and then when my forehand gets going I think I've been hitting my backhand really well this week. If I'm doing those three things, it's a good recipe.

"I grew up on this court when I was eight, nine, 10 years old. I showed up last year, and hopefully I can ride the wave with you guys and keep it going."

Fourth seed Bautista Agut beat compatriot Alejandro Davidovich Fokina 6-3 6-2, while the other Adelaide semi-final will see British player Jack Draper tackle South Korean Kwon Soon-woo.

Draper, who has been drawn to face Rafael Nadal in round one of the Australian Open, beat Russian third seed Karen Khachanov 6-4 7-6 (7-3), while Kwon saw off Swedish qualifier Mikael Ymer 6-1 6-2.

At the Auckland Open, second-seed Briton Cameron Norrie beat American Marcos Giron 6-1 6-7 (5-7) 6-2 to set up a last-four clash with another player from the USA, Jenson Brooksby, who edged past France's Quentin Halys 7-6 (7-3) 7-6 (7-2).

The other semi-final will be an all-French battle between Richard Gasquet and Constant Lestienne, who both came from a set down to see off David Goffin and Laslo Djere respectively.

The 18-year-old Fils, half the age of his opponent, won the first-round match against his fellow Frenchman 7-5 7-5 in Montpellier.

Fils will face another battle between youth and experience when he takes on Spaniard Roberto Bautista Agut in round two.

The 163-ranked Fils served eight aces and broke Gasquet four times to move into the next round

Nikoloz Basilashvili will face either defending champion Alexander Bublik or Gregoire Barrere in the last 16 after beating Constant Lestienne 6-3 (7-3) 7-5 6-2 in Monday's other match.