No. 4 seed Novak Djokovic of Serbia advanced to the finals of the Astana Open in Kazakhstan when No. 2 seed Daniil Medvedev of Russia retired with the match tied at one set each on Saturday.

Medvedev retired with a leg injury just after Djokovic won the second-set tiebreaker 7-6 (6). Medvedev won the first set 6-4.

In the final on Sunday, Djokovic will seek his 90th tour victory against the No. 3 seed, Stefanos Tsitsipas of Greece. Tsitsipas came from behind to defeat Russia’s Andrey Rublev, the No. 5 seed, 4-6, 6-4, 6-3.

Djokovic won the title in Tel Aviv last week. He leads Tsitsipas 7-2 in head-to-head matches.

Japan Open Tennis Championships

It will be an All-American final in Tokyo on Sunday, with No. 3 seed Taylor Fritz meeting No. 4 Frances Tiafoe.

Fritz was down 1-3 in the third set against Denis Shapovalov of Canada but captured the final five games to win 6-3, 6-7 (5), 6-3. Fritz will play in his third tour final of the season.

Tiafoe also needed three sets to advance, defeating South Korea’s Soonwoo Kwon 6-2, 0-6, 6-4.

The match was close, with each player winning 50 percent of both the total points and total games. The difference came down to the final set, when Tiafoe broke Kwon’s service twice.

–Field Level Media