BRITISH number one Elena Baltacha upset 30th-seed Kateryna Bondarenko at the Australian Open to ensure she would at least match her best-ever result at a grand slam.

Baltacha defied a rankings difference of over 50 places to win the second-round match 6-2 7-5 in one hour and 34 minutes.

The 26-year-old’s gutsy win means she will play in the third round of a grand slam for only the third time in her career, after advancing to the last 32 at Melbourne Park, in 2005, and at Wimbledon, in 2002.

It was also only the fourth win of her career against a top-50 rival and after reaching a career-high ranking of 83 earlier this month – which earned her direct entry to a grand slam for the first time.

Baltacha started confidently as she broke Bondarenko’s opening two service games to jump 3-0 ahead in the first set.

Bondarenko fought back to 3-2, but with her serve misfiring, Baltacha was again able to string a run of three games together to win the first set in 35 minutes.

Bondarenko did not win a single point on her second serve in the first set, as the Briton’s aggression, especially off her forehand, paid dividends.

The second set was a seesawing battle with Bondarenko racing 3-0 ahead on the back of some more consistent serving.

But again Baltacha, who beat Bondarenko’s sister Alona to reach the second round at Wimbledon last year, again put a run of games together.

The Briton won the next four, fending off three break points along the way, to steal the initiative and while Bondarenko broke again, Baltacha got her chance to serve for the match at 6-5 and did not waste the chance with the 23-year-old Ukrainian conceding the match when she hit a forehand long.

■ Eighth seed Jelena Jankovic ended Katie O’Brien’s Australian Open campaign in straight sets yesterday.

The Hull-born 23-year-old won through to the second round of a major for only the second time in her career when she defeated Patricia Mayr on Tuesday, but could not go a step further as she lost 6-2 6-2.

Jankovic broke O’Brien’s opening service game as she surged 3-0 ahead in the first set.

The games then went with serve until 5-2 when, after seven deuces, O’Brien was broken again to concede the set.

O’Brien had fended off four set points in the protracted game before Jankovic pounced on a short ball to fire a backhand cross-court winner.

In the fourth game of the second set, a double fault from O’Brien handed Jankovic a break to love, and the Serb did not relinquish the advantage, to win in one hour and 14 minutes.