Novak Djokovic wilted under pressure from Daniil Medvedev, falling 6-3, 3-6, 3-6 to the ninth-seeded Russian in the Cincinnati Masters semi-finals.
Former US Open champions Stan Wawrinka and Svetlana Kuznetsova received wildcards into the event on Tuesday along with two-time Australian Open winner Victoria Azarenka, tournament organisers announced.
World No. 11 Venus, beaten in this year's Australian Open final, was knocked out in the 2016 semi-finals and is chasing a first major title since winning Wimbledon in 2008.
Playing in her first final at the elite Premier Mandatory level, World No.15 Elena Vesnina battled through a tense three hours and one minute to subdue eighth-ranked Svetlana Kuznetsova.
Dominika Cibulkova hardly broke a sweat as she breezed past Germany's World No.31 Laura Siegmund while Caroline Wozniacki dumped Olympic champion Monica Puig out of the Sydney International
Caroline Wozniacki, who knocked out ninth-seeded former champion Svetlana Kuznetsova in the second round, defeated Monica Niculescu of Romania 6-3, 6-1. On the other hand, Roberta Vinci overcame a second set blip to defeat Carina Witthoeft 6-0, 5-7, 6-3
Serena Williams' complaints once again highlighted the issue of player safety at Wimbledon after France's Gilles Simon also threatened to sue when he was forced to play on during rain in his loss to Grigor Dimitrov last week
Serena Williams hit 43 winners and served 14 aces as she won the last nine games on Centre Court to remain on course for a record-equalling 22nd major title and a seventh Wimbledon crown
The 25-year-old Caroline Wozniacki from Denmark departed quickly on Tuesday after losing to 14th-seeded Svetlana Kuznetsova 7-5, 6-4.
Maria Sharapova, Svetlana Kuznetsova, Anastasia Pavliuchenkova, and Darya Kasatkina were named in the Russian women's singles team for the Rio Olympics
Victoria Azarenka beat two-time Grand Slam champion Svetlana Kuznetsova of Russia 6-3, 6-2 for her third Miami Open title.
Serena Williams suffered a shock defeat at the hands of Svetlana Kuznetsova while Andy Murray went down to Grigor Dimitrov.
Julia Goerges cruised past double Grand Slam winner Svetlana Kuznetsova 6-0, 6-1 in the first round of the Dubai Tennis Championships.
Svetlana Kuznetsova took just 55 minutes to claim a 6-0, 6-2 victory over Monica Puig in a one-sided final at the Ken Rosewall Arena.
Svetlana Kuznetsova beat Sara Errani of Italy in straight sets while Grigor Dimitrov recorded a 7-6(2), 6-4 win over Uruguay's Pablo Cuevas.
Svetlana Kuznetsova defeated Anastasia Pavlyuchenkova 6-2, 6-1 in the final in one hour 18 minutes.
Anastasia Pavlyuchenkova, defending champion of Kremlin Cup,
Russia's Kuznetsova, the winner of 2009 French Open and 2004 US Open, lost the lop-sided match 0-6, 1-6 to her compatriot Anastasia Pavlyuchenkova.