World number one Aryna Sabalenka has criticised the Women's Tennis Association over the organisation of its season-ending Finals in Mexico.

"I am very disappointed with the WTA and the experience so far at the WTA Finals," said the Belarusian.

"This is not the level of organisation we expect for the Finals."

The venue for the Finals was only confirmed in early September after talks between the WTA and Saudi Arabia failed to yield an agreement for 2023.

The construction of the court in the Mexican resort of Cancun was only completed in the days before the tournament's Sunday start.

Players had been mostly supportive of playing the tournament in Saudi Arabia, but there was criticism from the likes of Martina Navratilova and Chris Evert of the WTA potentially going to a country where women face discrimination.

Although Sabalenka dominated against Sakkari, converting five of her nine break-point chances and winning 11 games in a row to wrap up victory in an hour and 14 minutes, she said the conditions were far from ideal.

"To be honest, I don't feel safe moving on this court a lot of the time," Sabalenka said.

"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.

"As I said in my press conference tonight, as a player I really feel disrespected by the WTA. I think most of us do."

Sabalenka took the top ranking from Poland's Iga Swiatek after the US Open in September and will finish as year-end number one if she is undefeated in round-robin play or reaches the final.

Earlier in Group A, American Jessica Pegula beat Elena Rybakina 7-5 6-2.

Pegula, 29, won 10 of the last 12 games against her Kazakh rival, who had served for the first set at 5-3 but had 35 unforced errors in the match.

Sabalenka's next match will be on Tuesday against Rybakina, with Pegula facing Sakkari.

Monday's Group B matches see Swiatek take on Wimbledon champion Marketa Vondrousova while US Open winner Coco Gauff faces Ons Jabeur.