Top seeds Daniil Medvedev and Iga Swiatek were heavy favourites to claim their respective titles as play began at the US Open on Monday.
Medvedev was the +260 favourite at BetMGM to defend the men's title ahead of Spaniards Rafael Nadal (+400) and Carlos Alcaraz (+550). Medvedev claimed his first career Grand Slam title at last year's US Open, where he denied Novak Djokovic from winning the "Calendar Slam."
Djokovic is not in this year's event because of COVID-19 vaccination requirements. World No. 2 Alexander Zverev, who was a US Open finalist in 2020, also withdrew due to ankle surgery.
Medvedev opened as the +225 favorite at BetMGM but has seen his odds lengthen slightly despite the absence of two of his top threats. He has had a rollercoaster 2022 since falling to Nadal in the Australian Open final.
He has risen to No. 1 in the world despite missing two months following hernia surgery. Medvedev also missed out on Wimbledon due to the tournament's decision not to allow players from Russia to compete because of his country's ongoing war against Ukraine.
Medvedev is 34-12 in 2022 entering Monday's first-round match against unseeded American Stefan Kozlov. He also leads BetMGM with 21.0 percent of the total bets to win the men's title along with 41.9 percent of the handle.
That makes Medvedev the second-biggest liability in the men's draw behind Wimbledon finalist Nick Kyrgios. Kyrgios opened as a +3300 but began the tournament at +800 as he has been backed by 15.0 and 13.3 percent of the action, respectively.
Nadal is the third-biggest liability as the 36-year-old chases his 23rd Grand Slam title and third of the year after also winning the French Open for a 14th time. He has drawn 15.8 percent of the total bets and 12.8 percent of the handle.
Swiatek is almost as popular with the public on the women's side as Medvedev has been on the men's.
She opened at +1400 but has seen her odds shorten to +450 as the Polish star has been backed by 20.4 percent of the total bets to win the women's title and 31.2 percent of the handle.
That makes Swiatek the biggest liability at BetMGM to begin play at Flushing Meadows.
She's ahead of Serena Williams, the sentimental favourite as she plays what is expected to be the final tournament of her career. A +3300 longshot to win a record-tying 24th Grand Slam, Williams has still been backed by 9.8 percent of the bets and 11.7 percent of the handle -- second most at the sportsbook.
Fellow American Coco Gauff, the No. 12 seed, is the third-biggest liability, having drawn 13.0 and 11.1 percent of the action, respectively. Gauff's odds have shortened from +2000 to +1600 as she seeks her first Grand Slam title.
