+ A
A -
DPA
London
Novak Djokovic moved a step closer to a record-equalling sixth ATP Finals crown with a 6-4, 6-1 win over Germany's Alexander Zverev in London on Wednesday.
The 31-year-old Serb is now unbeaten at the top of the Guga Keurten group with a 2-0 record.
Djokovic will advance to his eighth year-end championships semi-final if American John Isner beats Marin Cilic or if Cilic wins in three sets after the evening session.
The world number one broke late in the first set and twice in the second set to complete the victory in 76 minutes.
"I don't think it was breathtaking tennis, but a win is a win," said Djokovic.
"He wasn't close to his best in the second set so it looked a bit easier than expected because he served very well in the first set, but it dropped in the second set and allowed me to step in."
However, Zverev had the first two break point opportunities at 4-4 after Djokovic double-faulted, but the Wimbledon and US Open champion escaped with a drop shot to remain ahead. And a double-fault from Zverev in the next game gifted Djokovic the set after 48 minutes.
"Obviously I had chances in the first set," said the 21-year-old world number five.
"If I break him at 4-All, we'll see where the match goes. I think the match was much closer than the score says.
"Hopefully I still give myself the best chance to be in the semifinals."
Djokovic's run of 22 matches unbeaten ended at the Paris Masters final with a defeat to Karen Khachanov. Djokovic was struggling with flu symptoms at the time.
The same issue returned in London, where Djokovic often used tissues to wipe his nose between games.
"Somehow I managed to gather the strength when I needed it," said Djokovic.
"I think also it seemed like Sascha was not feeling really great, definitely not playing well, especially from the back of the court.
He made a lot of errors."
The second set was much quicker as more unforced errors started to build to a match total of 36 for Zverev, and a long backhand conceded the first break for a 3-1 Djokovic lead.
"I just started missing unnecessary balls," said Zverev.
"Novak, when he's in the rallies, he's obviously very hard to beat.
