Sela had taken the Ukrainian to a third set but called it quits after one game as sunset drew closer, which marks the beginning of Yom Kippur.
The match was scheduled second on the main court and the Israeli had requested that his match be moved forwards to be completed before sunset, but his request was denied.
It is believed Sela forfeited $34,000 in prize money and 90 rankings points with the retirement. He is currently ranked 77th in the world and his last appearance in an ATP tour level final was in Atlanta three years ago.
Sela’s clash with Dolgopolov followed Henri Laaksonen’s meeting with China’s Zhizhen Zhang, who stunned fourth-seed Paolo Lorenzi earlier in the week.
That battle went the distance and it became apparent that Sela may not be able to finish his match before sunset, expected at 6:12 PM local time, unless it was completed in straight sets.
Laaksonen’s victory spanned two hours and five minutes while it took an hour and 13 minutes to wrap up two sets in Sela’s clash. The Israeli converted his only break point opportunity to claim the second set 6-4.
The world number 77 had upset third-seed Mischa Zverev in the previous round and it was widely assumed that Zhang was scheduled to play first — action began at 2 PM local time — to appease the home crowd.
The tie was extended for an extra day by the ITF to accommodate the holiday after the Belgian Tennis Association turned down Israel’s initial request to postpone matches that day.
Israel was instead fined for the inconvenience of adding an extra day to proceedings.