Sixth seed Venus Williams will play 16th seed Li Na in the quarter-finals of the Australian Open after both women won their fourth-round matches on Monday.
In an encounter that featured 13 breaks of serve, Williams battled back from a set down to defeat Italian Francesca Schiavone 3-6 6-2 6-1 in just under two hours.
It was far from convincing by the American, who looked down and out after she lost the first set and went down a break in the second.
Both players struggled to hold serve from the outset, with Williams winning just one point in her first two service games.
Schiavone, seeded 17, got the vital break in the eighth game and then sealed the set with her third ace of the match in the next game.
Williams was far from her best, hitting just three winners and committing 14 unforced errors in the first set.
She continued to struggle at the start of the second with Schiavone breaking to love in the opening game. But that seemed to just kick Williams into action as she went on to win six of the next seven games to force a deciding set.
Schiavone again broke in the first game of the final set to seemingly gain the upper hand, but then Williams reeled off six straight games to close out the match.
Williams was delighted to come away with a win, especially after Schiavone was on top early on.
"She played really well in the first set. I have to give her credit. She just played really aggressively. She was making her shots, doing everything she needed to do to win the match," Williams said.
"But obviously it takes a lot to close out a match, especially on an important match like that one. I was able just to get some footing back in and start to execute the way I wanted to."
In another encounter where players struggled to hold serve, Li defeated Denmark's fourth seed Caroline Wozniacki 6-4 6-3 in a match that featured 12 service breaks.
After going down 2-4 in the opening set, a dominant Li won six straight games to take the first set and go up a break in the second.
Wozniacki immediately broke back, but when Li broke again in the next game, the Dane called for a medical timeout for treatment on her right thigh.
She battled on bravely but there was no stopping Li as she booked her spot in the last eight of a Grand Slam for the second time in her career, having made the quarters at the US Open last year.
Wozniacki was left to lament a missed opportunity after claiming a 4-2 lead in the opening set.
"I had my chances, especially in the first set leading all the time. Had my chance for 5-2. I didn't take it," she said.
"Then she started well with the new balls. It turned around a little bit. I tried to hang in there. But, yeah, didn't go my way today."