Daniil Medvedev has played down his chances of taking Novak Djokovic's spot as world number one before the end of the year, describing the task as "almost impossible".
The Russian beat the 20-time Grand Slam champion in straight sets to claim his first major championship at the 2021 US Open.
And while Medvedev could be in line for a significant boost before the end of the season as he bids to defend his ATP Tour Finals title in Turin, he does not believe he will be able to overhaul Djokovic.
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"Honestly, it seems almost impossible to me,” Medvedev explained on the eve of the Laver Cup.
“I have to defend my titles, [in Paris] and at the [ATP Finals].[Djokovic] doesn’t have a lot of points to defend, I think, but what remains [of the calendar]?'" Medvedev asked.
“[There are events in] Indian Wells, [Paris], Turin and Vienna.
“Vienna, I will not play, because it is the week of St. Petersburg. I don’t think I’ll go to St Petersburg either but if I play somewhere that week it will be [there].
“So there are Indian Wells, Paris and Turin left. If I win all three I might be in the game, but it’s still a huge challenge."
Medvedev will play in his first Laver Cup as Team Europe bid to secure victory in the event for the fourth consecutive edition.
Captain Bjorn Borg has a strong team at his disposal in Boston, with Medvedev joined by Stefanos Tsitsipas and Alexander Zverev, among others, as they take on John McEnroe's Team World.

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The Russian does not believe he will feature much in the doubles, admitting that he is a weaker player with four men on court.
"I'm really excited to represent Team Europe," Medvedev said. "It is my first experience so I don't know what to expect. I know the format, just want to bring the most points possible for my team in singles because I don't think I'm playing doubles...I'm not really good!
"I want to see how it is, it is not the same on TV or when you are playing. So just looking forward for my first match and for the first match of Casper [Ruud] also to see how it is on the bench."
The Norwegian Ruud opens against powerful server Reilly Opelka (USA) on the hard court at TD Garden.
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