Sabalenka recorded her tour-leading 31st victory this season on the Madrid clay, adding the WTA 1000 trophy to titles in Brisbane and Miami.
The fourth-seeded Djokovic suffered a second consecutive opening defeat, after losing his opener against Alejandro Tabilo in Monte Carlo two weeks ago.
Iga Swiatek admits the strict doping protocols can be stressful for players but feels like she has "been through the worst" after surviving her positive test over contaminated melatonin.
The 38-year-old Spaniard, winner of 22 Grand Slam trophies, including 14 at Roland Garros, retired from the sport after his final match at the Davis Cup in Malaga in November.
The top-seeded Zverev, appearing in his first final since losing to Jannik Sinner in the Australian Open title decider in January, had little trouble dealing with Shelton, ranked 15 in the world.
The fifth-ranked Djokovic struggled to find his rhythm in a 6-3, 6-4 loss to Chilean Alejandro Tabilo in the second round, making an inauspicious start to his clay season.
The 19-year-old said that he had filled out his withdrawal form ahead of his match with Spaniard Roberto Bautista Agut and went to the referee's room -- but the official was out for lunch.
The Spaniard world number three, speaking ahead of the Miami Open, said he had not been given any notice of the legal case from the Professional Tennis Players' Association (PTPA) or the strongly-worded statement issued on Tuesday.
A four-time Grand Slam champion, Alcaraz said he was too focused on what weapons British left-hander Jack Draper might bring and unable to calm the pre-match jitters that prevented him from rising to the occasion.
Zheng Qinwen became the first Chinese player to win Olympic tennis singles gold when she defeated Croatia's Donna Vekic on Saturday, hailing her victory as a "proud" moment for herself and her country.
They started dating in 2020 but recently were rumoured to have split. "That's our personal life so you don't need to know that," said 29-year-old Siniakova.
Andy Murray's trophy-filled career came to an end at the Paris Olympics on Thursday as another chapter closed on tennis's golden generation.
World number three Carlos Alcaraz edged closer to an Olympic Games showdown against Novak Djokovic on Thursday with a storming display which brought the queen of Spain to her feet.
World number seven Zheng triumphed 6-2, 7-5 and will face either Croatia's Donna Vekic or Anna Karolina Schmiedlova of Slovakia in the gold medal match.
Matthew Ebden had not expected to last long against Novak Djokovic in the first round of the Olympics on Saturday and he was not wrong - but it left the Serbian wondering why the Australian doubles specialist was competing in the singles.
The 38-year-old effectively ruled himself out of the singles tournament as he battles a thigh injury picked up in training at Roland Garros, the scene of 14 of his 22 Grand Slam triumphs.
The Italian said he was "sad and disappointed" to drop out, adding that he had started feeling unwell on Monday after a practice week in Monaco.
The 37-year-old, a two-time Olympic champion, is planning to play in the singles and doubles at his fifth Games.
The 38-year-old Spanish left-hander has a protected ranking of ninth to put himself into the field for the Flushing Meadows fortnight, which begins on August 26.
