Johanna Konta began the new year with an impressive win over Madison Keys at the Brisbane International to wipe away memories of her dismal end to 2017.

Konta, the No5 seed, ended her season early because of injury, split with her coach and had not won a match since August when she came to Brisbane. But she started 2018 with intent after a come-from-behind 4-6, 6-4, 6-3 success over the US Open finalist.

It was the toughest first-round draw possible for the British No1 against a player ranked No19 in the world and she lost the first set by dropping her serve at 4-5.

It was the first match under her new coach, Michael Joyce, who used to work with Maria Sharapova, and Konta began to get on top, a break midway through the second set enough for her to get level.

She then took Keys’ serve in the opening game of the decider and saw it out comfortably to end a run of five successive defeats, going back to the Cincinnati Open in August.

Konta said: “It was my first match in quite a while and it was a tough first round, Madison is a great player. She has a big game so when my chances came I had to take them.”

The two-time Wimbledon champion Petra Kvitova, meanwhile, was forced to withdraw from the tournament because of a virus she picked up on the flight to Australia.

The 27-year-old Czech was unable to take the court in her first round match against Anett Kontaveit and was replaced in the draw by Heather Watson, who subsequently lost 6-0, 6-3 to the Estonian.

former world No2 required four hours of surgery on her left hand in December 2016 after being attacked by a man wielding a knife who had gained access to her apartment by posing as a utility worker. Kvitova returned to action, after months of rehabilitation, during the French Open in May and went on to win the Aegon Classic in June.

Elsewhere, Sharapova and the top-ranked Simona Halep opened their seasons with straight sets wins at the Shenzhen Open.

Sharapova finished off a 6-3, 6-0 win over Mihaela Buzarnescu with a powerful forehand winner, and Halep started her bid for a second Shenzhen title with a 6-4, 6-1 victory over Nicole Gibbs.

“It’s my first victory this year as No1 in the world, so I’m just happy and enjoying the time,” said the 2015 champion, Halep, who was due to play China’s Duan Yingying in the next round.