London - Chinese sixth seed Li Na came through a disjointed match with Czech 32nd seed Klara Zakopalova on Saturday to book her place in the Wimbledon fourth round.
The 2011 French Open champion won 4-6, 6-0, 8-6 in a two-hour third round contest after nearly blowing it in the final set.
However, Li recovered her nerve to finish off her opponent and secure a match against Italian 11th seed Roberta Vinci for a place in the quarter-finals.
Zakopalova, who at 31 is two days older than Li, entered Wimbledon having lost her previous six matches.
The Czech number three, whose best result at Wimbledon was reaching the fourth round in 2010, had the better of a fairly even first set but could not get a game in the second as Li found her rhythm.
However, the Chinese number one could not sustain her dominance in the third set, which went down to the wire and could have gone either way.
Baseliner Zakopalova broke Li to make it 6-5 in the deciding set.
Forced to break back to stay in the tournament, Li capitalised on some poor serving and broke with a stunning forehand winner down the line.
Li held serve then had a match point at 7-6 but was reined in by Zakopalova. However, she capitalised on her second match point to take the tie on the 2,000-seater Court 3, where she was cheered on by fans waving the Chinese flag.
It was the second time Li had beaten Zakopalova this year, having won the inaugural Shenzen final at the start of the year.
Li made the last 32 by overcoming Romania's in-form Simona Halep with a similarly roller-coaster performance, winning 6-2, 1-6, 6-0 on Thursday.
Li's Wimbledon best was reaching the 2006 and 2010 quarter-finals, though she tumbled in the second round on her last two All England Club outings.