Coetzer beat Graf at the Australian Open and then handed the world’s No. 2 ranked player the worst defeat of her career when she beat her 6-0, 6-1 at the German Open last month.
``It was very tough in the last few games. She was starting to play better the last few points, I felt lucky to win the last point,″ Coetzer said.
Of the 78 points Coetzer won in the one hour, 32-minute match, 64 came on unforced errors by Graf.
Earlier, Filip Dewulf became the first qualifier to reach the semifinals of the French Open when he beat Magnus Norman of Sweden 6-2, 6-7 (2-7), 6-4, 6-3 in a men’s quarterfinal.
In a match between two unseeded players, the turning point came late in the third set. Norman wasted four break points and received a warning for smashing his racket to the ground.
Norman dropped his serve in the next game to fall behind 5-4 and he never recovered. Dewulf served out the set and cruised through the last one, clinching the match on a forehand winner.
Dewulf, No. 124 in the world, set a personal and Belgian Grand Slam best by reaching the semifinals.
Only two qualifiers previously have reached the semifinals of Grand Slam tournament in the Open era, both in 1977, Bob Giltinan at the Australian Open and John McEnroe at Wimbledon.
At least two unseeded players will be in the semifinals.
Earlier, Iva Majoli reached the first Grand Slam semifinal of her career when she beat doubles partner Ruxandra Dragomir 6-3, 5-7, 6-2 in the women’s quarterfinals.
The seventh-seeded Croatian collapsed to the ground with relief after the two-hour, 23-minute battle and while she lay on her back, Dragomir slowly somersaulted over the next and lay next to her. Then they got up and walked away with their arms around each other. Dragomir was the only unseeded player in the women’s quarterfinals.
``I was really exhausted, she was chasing every ball,″ Majoli said.
Serving for the match at 5-3 in the second set, Majoli squandered one match point and dropped her serve.
Dragomir saved two more match points in the next and won four straight games to force a third set.
Majoli went up 5-2 and Dragomir received treatment for a groin injury during the changeover. Although Dragomir was visibly hampered by the injury, Majoli needed three more match points before putting it away with a volley.
On the men’s side, no player has been able to establish his mark on clay so far this year and the trend has held true, with six unseeded players reaching the quarterfinals, a Grand Slam record.
The only seeds left are No. 3 and defending champion Yevgeny Kafelnikov and two-time winner Sergi Bruguera, No. 16.