the Australian Open, after a straight sets win over Patricia Mayr.
The 23-year-old British number two won 6-3 6-3 to progress past the first round of a grand slam for just the second time in her career.
O’Brien’s best ever result at a major was reaching the second round at Wimbledon in 2007 and a confident display, against a player ranked three places behind her in 90th, ensured she would at least match that.
She will play the winner of the match between eighth seed Jelena Jankovic and Monica Niculescu later today.