Highly-rated French defender Upamecano agreed fresh terms through to the summer of 2023
The news come as a blow to Arsenal, who were reportedly eyeing a move for the centre-back.
But Leipzig showed no sympathy to the Gunners on social media with their announcement of Upamecano’s contract extension.
Shortly before officially announcing the news, the German club simply tweeted “Ring ring” alongside a telephone emoji.
“Is that Arsenal phoning for Upamecano?” one user asked.
They quoted the tweet, replying: “*rejects call*.”
Arsenal and Manchester United had been linked with a move for Upamecano, who has made 111 appearances for Leipzig.
Sporting director, Oliver Mintzlaff, for the ambitious German club recently admitted that the club would have to sell Upamecano if they could not agree a new deal with the 21-year-old.
Her told Bild: "Upa is an extremely important player for us and one of the most sought-after talents in Europe.
"And we can assure that we have a clear understanding with him and his agent he won't leave us on a free. We can't afford that as a club.
"There are only two options: prolong or leave. I am sure we'll soon find out in which direction it's going."
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The France youth international joined Leipzig from Austrian outfit Red Bull Salzburg in January 2017, one of a number of players to make the switch between the affiliate clubs in recent years.
Hannes Wolf made the switch last summer for £10m, while Amadou Haidara completed the same transfer the year before.