Kvitova serves AO warning in Adelaide win

Petra Kvitova has sent a reminder to the Australian Open field she is no spent force, showing off her powerful serve in defeating fellow Wimbledon champion Elena Rybakina in Adelaide.

The Czech 32-year-old arrived for the second instalment of the Adelaide event in good spirits after an impressive United Cup campaign and it showed in a 6-3 7-5 first round win.

Kvitova won Wimbledon in 2011, when she peaked at No.2 in the world, before adding another All England triumph in 2014.

Rybakina became the first Kazakhstani player to win a major title at Wimbledon last year but couldn't make a dent on the Kvitova serve on Monday.

"I lost (to her) last season and she played really great, serving really well, so I focused on my serve, waited for my chances to break her," said Kvitova, ranked 16 in the world.

"And my serve worked very well today, it's what I'm very happy with ... it was about (dominating) the serve and first one or two points of the rallies.

"I enjoyed the United Cup and playing with the guys ... it was a different vibe and gave me great practice, great attitude as well so I came here playing very well."

The left-hander will play the winner of Shelby Rogers and Zheng Qinwen in the second round.

Last year's Australian Open finalist Danielle Collins was in fine touch too, racing to a 5-0 lead over former world No.1 Karolina Pliskova before prevailing 6-2 6-4.

"I was wondering whether it was going to happen at 1-0, 2-0, 3-0 and then at 5-0 she hit some great shots that were too good," Collins said of the power at Pliskova's disposal.

"I had to make some adjustments and get back into it, stay calm.

"But I don't think Karolina was at her best. It's ups and downs with the tennis and (about) just riding it out.

"I know how that is being on the other side of it, hopefully I can keep playing my best tennis."

Collins' next assignment is Swiss qualifier Jil Teichmann, also fresh off United Cup duties, who beat Anastasia Pavlyuchenkova 7-5 6-4.

World No.13 and 2020 Olympic gold medalist Belinda Bencic was impressive in dispatching two-time grand slam winner Garbine Muguruza 6-3 6-4.

Bencic, who served strongly and didn't face a break point, is coming off a mixed United Cup where she beat Yulia Putintseva but lost to world No.1 Iga Swiatek.

She'll next meet Jelena Ostapenko or qualifier Anna Kalinskaya.