ST. PETERSBURG — Top seed Petra Kvitova shook off her Australian Open hangover to beat Belarusian Victoria Azarenka 6-2, 7-6 (7-3) in the St Petersburg Ladies Trophy on Wednesday, but not before the former world No. 1 gave the Czech a scare.

Kvitova, the defending champion, showed she was still feeling the effects of Saturday's defeat by Naomi Osaka in the Australian Open final as she lost her first two service games.

The world No. 2 managed to break back immediately on both occasions before holding for the first time, and then used her powerful groundstrokes to dominate the longer rallies and claim the opener.

With her serve firing, Kvitova charged out of the blocks in the second set, winning the first three games to spark what looked to be a stroll into the quarter-finals and breaking Azarenka's serve again to open up a 5-1 lead.

But the Czech double faulted on match point, allowing Azarenka to break back and mount what was almost a fightback for the ages.

"I don't know why (the double fault) happened. I really wanted to finish it earlier but unfortunately I had to fight in the second set and I did quite well in the tiebreak," Kvitova said courtside after her win.

Azarenka, her confidence restored, pinned Kvitova back behind the baseline with her aggressive tennis, and broke again to level the set at 5-5 and force a tiebreak.

Kvitova hit 40 winners to Azarenka's 14, but she also made 33 unforced errors compared with 17 from her opponent.

The Czech's composure came to the fore in the tiebreak and she closed out the match with a powerful backhand down the line to set up a quarte-final clash with either Russia's Veronika Kudermetova or Croatia's Donna Vekic.

Ex-No.1's clash in Fed Cup

as Czechs host Romania

Two former world No. 1 players are set to clash in the Fed Cup first round as holders the Czech Republic take on Romania on Feb. 9-10, team nominations showed on Wednesday.

World No. 5 Karolina Pliskova will spearhead the Czech Republic, while third-ranked Simona Halep is due to lead the Romanian team.

Pliskova was the world No. 1 for seven weeks in 2017, while Halep led the rankings for a total of 48 weeks before being replaced by Australian Open champion Naomi Osaka on Monday.

"Simona Halep is coming so it's going to be a big battle," Pliskova wrote on her website. Pliskova, an Australian Open semifinalist, will team up with 38th-ranked Katerina Siniakova, the world No. 1 for doubles, 73rd-ranked teenager Marketa Vondrousova and doubles specialist Barbora Krejcikova.

Siniakova emerged as an unexpected team leader in last year's final when she won both her singles to hand the Czechs a 3-0 win against the United States and their sixth Fed Cup title out of the last eight editions.

"I'm glad we have a very strong team," said Czech captain Petr Pala, who will miss Australian Open finalist and world No. 2 Petra Kvitova for the tie in the eastern Czech city of Ostrava.

"Petra Kvitova has excused herself and I understand and respect this, considering her program," Pala added. Kvitova, the Wimbledon champion from 2011 and 2014, is defending last year's titles from St Petersburg this week and Doha the week after the Fed Cup tie.

Besides Halep, Romanian captain Florin Segarceanu has called up 28th-ranked Mihaela Buzarnescu, Irina-Camelia Begu (71), Ana Bogdan (99) and Monica Niculescu (100), according to the Fed Cup website.

"It will be terribly tough, the Romanian team is strong and the chances are 50-50," said Pala. In their last head-to-head encounter, the Czechs beat Romania in Cluj 3-2 in the first round in 2016.

Errani back in Italy's Fed Cup

team after doping ban

Former French Open finalist Sara Errani was named Wednesday in Italy's Fed Cup team for their World Group II first round clash against Switzerland after returning from a ten-month doping ban.

Errani, a five-time Grand Slam doubles champion, had her ban for an anti-doping violation increased last June from two to 10 months by the Court of Arbitration for Sport (CAS).

Errani is eligible to play Feb. 8 and the matches are scheduled for the two following days, Feb. 9-10. The Italian, a Roland Garros finalist in 2012, was suspended for two months in August 2017 by an independent tribunal of the Italian Tennis Federation after she failed an out-of-competition test, administered at her family home, last February.

Errani said she had consumed letrozole, which can have a "marginal" anabolic effect and mask the use of testosterone, unknowingly when her mother's cancer medication somehow found its way into a family meal.

The CAS decision followed appeals by the Italian anti-doping agency, which asked for a longer ban, and Errani, who wanted it overturned. But she was told she would have to serve another eight months of suspension.

Italy Fed Cup captain Tathiana Garbin called up Errani, now ranked 113th, for the tie against Switzerland in Biel. The former four-time Fed Cup winners' team also includes 27th-ranked Camila Giorgi, Martina Trevisan (170), Jasmine Paolini (199) and Deborah Chiesa (264). — Agencies