Serena Williams battled through a tough fourth-round clash with Barbora Strycova to reach the Australian Open quarter-finals.
The world No. 2 was well below her best in the first set, and was broken three times, but still had enough to win 7-5 6-4 against Strycova.
The Czech 16th seed, 30, had lost both her previous meetings with the American and was yet to take a set.
And that continued on Rod Laver as Williams progressed to the quarter-finals, where she will face either Johanna Konta or Ekaterina Makarova.
Strycova got off to the perfect start as she set up three break points in game one and she took full advantage to break at the second time of asking.
Williams immediately broke back but continued to struggle in her second service game and was broken again.
The 35-year-old won only one point of nine played in her opening two games on serve in what was a very shaky start.
Fortunately for the world No. 2, Strycova was serving equally poorly and matched Williams total of one point on serve in her opening two games.
Both finally found their feet and held for 3-3 but Strycova again took an advantage by breaking for 4-3.
Once again, as was the case throughout the first set, the Czech failed to consolidate the break and Williams levelled for 4-4.
Strycova came under major pressure at 4-5 but impressively saved four set points, including a neat serve-and-volley play, to move to 5-5.
The Czech was pushed hard again at 5-6 but her resistance was finally broken on Williams’ eighth set point after the American was gifted a fortunate net cord.
After both held in their opening games of the second set, Williams then got the breakthrough at the start of the second and looked on course for the win.
However, when serving for the match, Williams faltered and Strycova broke back for 4-5 but the second seed immediately hit back to see it out.