Cancun was announced as the host of the governing body’s showpiece event less than two months ago, with the first matches taking place on Sunday night.
World number one Sabalenka easily defeated Maria Sakkari 6-0 6-1 but took to social media afterwards to criticise the arrangements for players, who were only able to practise in the temporary arena for the first time on Saturday.
Writing on Instagram, Sabalenka said: “I’m happy that I was able to stay focused tonight, overcome the conditions, and play well.
“I have to say, though, that I am very disappointed with the WTA and the experience so far at the WTA Finals. As a player, I feel really disrespected by the WTA. I think most of us do.
“This is not the level of organisation we expect for the Finals. To be honest, I don’t feel safe moving on this court a lot of the time, the bounce is not consistent at all, and we weren’t able to practise on this court until yesterday for the first time.
“It’s just not acceptable to me with so much on the line and so much at stake.”
A highly lucrative deal with Shenzhen to stage the WTA Finals began in 2019 but was disrupted by Covid-19 and has not resumed following the tour’s break from China over the disappearance of Peng Shuai.
This is the third year in a row that a late decision has been made about the host of the tournament, with Guadalajara stepping in in 2021 before it headed to Fort Worth in Texas last year, where the main headlines were about poor attendance.
There had been intense speculation this year that the WTA Finals would head to Saudi Arabia, and the one-year deal with Cancun has very much left the door open for next season and beyond.
Sabalenka won the first 11 games before Sakkari, a replacement for the injured Karolina Muchova in the season-ending championships, got on the board.
American Jessica Pegula fought back from a break down in the first set to beat world number four Elena Rybakina 7-5 6-2.
Trailing 5-3, Pegula won four games in a row to clinch the first set and continued her record of not losing a match this year after going a set up.
Play in the other group begins on Monday night with world number two Iga Swiatek taking on Wimbledon winner Marketa Vondrousova before US Open champion Coco Gauff meets Ons Jabeur.