Justine Henin continued her impressive return to tennis when she fought back to beat former World No 1 Jelena Jankovic 3-6, 7-6, 6-3 in Stuttgart on Friday, leaving her opponent exasperated.
Jankovic was kicking herself when, having won the first set, she failed to take a break point which would have put her 6-5 ahead in the second.
Instead, seven-times Grand Slam winner Henin, who returned this year from a 19-month break, won the set in a tiebreak before wrapping up the win.
"As soon as you lose your ground or drop you level, she is right there, she comes right at you, she takes advantage, she has all the experience," said Jankovic.
"I felt I was really going to win and I had everything under control, it was just a few points here and there that didn't go my way.
"I had everything under control, I was more aggressive than her - it was frustrating. As soon as you drop your guard, she takes her opportunities."
Henin won all four of her break points in the match while Jankovic converted only three out of nine.
The Belgian, whose grand-slam haul includes four wins at Roland Garros, will face unseeded Israeli Shahar Peer in Saturday's semi-final at the indoor clay tournament.
Peer upset second-seed and another former number one Dinara Safina 6-3 6-2.
"I still need time to get used to clay," Henin told reporters. "I haven't played on this surface for two years. I grew up on this surface and my best results are on this surface but I try to be a complete player."
Wildcard Henin, runner up at the Australian Open in January, added: "It's only my fifth tournament back, it's normal to have ups and downs.
"I feel fresher than two years ago, I really needed the time off. Just to have the experience which I didn't have before as a person gives me a lot."
Australia's Samantha Stosur also went through to the semi-finals with a 6-3, 6-3 win over China's Li Na.
