Match detailsFixture: Novak Djokovic vs Alexander ZverevDate: 20 November 2020Tournament: Nitto ATP Finals 2020Round: Round-robin stageVenue: London, United KingdomCategory: ATP FinalsSurface: Indoor hardcourtPrize money: $5,700,000Match timing: Not before 2 pm GMT, 7.30 pm ISTLive telecast: USA - ESPN / Tennis Channel | India - Sony / Sony LivNovak Djokovic vs Alexander Zverev previewNovak Djokovic, the top seed at the ATP Finals, suffered a surprising loss to Daniil Medvedev in his second game of the Round Robin stage. The Serb was thumped 6-3, 6-3 by the 24-year-old, and is now in danger of getting knocked out from the tournament.Djokovic couldn't handle the well-thought-out gameplan from Medevedev, who refused to give the Serb any room on the baseline. The World No. 1 lost his serve thrice in the match, while he was unable to break Medvedev even once.Since Djokovic won his opening match against Diego Schwartzman, he will now face Alexander Zverev in a do-or-die encounter to keep his semifinal hopes alive. Both Djokovic and Zverev have one win and one loss to their name.A Med on a mission.Daniil Medvedev takes down the World No. 1 in London! #NittoATPFinals pic.twitter.com/4UkrDx8gWL— US Open Tennis (@usopen) November 18, 2020The German, however, seems to be in better shape than Djokovic right now. He lost his first match against Medvedev, but fought through three sets against Schwartzman on Wednesday to get on the board.Zverev smacked 10 aces and won 73% of his first-serve points against Schwartzman, quashing a late comeback from the Argentine to win 6-3, 4-6, 6-3.The 23-year-old might be the more confident player going into the game on Friday, given his recent form. He had finished as the runner-up in the last tournament he played, the Paris Masters, which included a win over Nadal. Zverev had also made it to the semifinal of the season-ending event last year, after having won the 2018 edition.Novak Djokovic vs Alexander Zverev head-to-headNovak Djokovic and Alexander Zverev have faced off five times on tour so far, with the Serb leading the head-to-head 3-2.Three of their first four encounters were semifinals or finals, with Zverev winning twice. Both his wins were in tournament finals - including one at the 2018 ATP Finals.Djokovic, however, won the most recent encounter between the duo, at Roland Garros 2019. The duo are tied 1-1 in the head-head-head on indoor hardcourts.Novak Djokovic vs Alexander Zverev predictionWhile Novak Djokovic has a slight edge over Alexander Zverev in the overall head-to-head, the German is the more in-form player coming into this match. However, they are both facing the pressure of external factors, and the result on Friday could well depend on who blocks out the distractions better.Djokovic has had to deal with massive criticism due to his shenanigans this year, while there are domestic abuse allegations hanging over Zverev. In that context, it will be vital for both players to stick to the basics in the match and focus on their own game.Alexander Zverev has been accused of physical and verbal abuse by his ex girlfriendDjokovic's return of serve looked surprisingly meek against Medvedev. He will need to improve upon that in this match, particularly since Zverev is a big and powerful server too.However, Zverev has been having issues with double faults, and his forehand has been a little hit-or-miss too. All things considered, the World No. 1 might just have enough experience to edge Zverev in a tight battle.Prediction: Novak Djokovic to win in three sets.