Rafael Nadal converted only four of 19 break-point chances yet still beat James Blake 3-6, 6-3, 6-1 in the quarterfinals of the Sony Ericsson Open on Wednesday. Jelena Jankovic advanced to the women's semifinals when Elena Dementieva retired with a back injury trailing 6-3, 3-1. Nadal's first service break came with a ferocious backhand passing shot for a 5-3 lead in the second set. He broke three more times in the final set, including on the final point. When a demoralized Blake hit his last forehand long, Nadal leaped and punched the air. On Friday he'll play 10th-seeded Tomas Berdych, who beat No. 31 Igor Andreev 6-4, 6-4. Dementieva said her back began bothering her on Tuesday, and she called it quits against Jankovic after 58 minutes. No. 4 Jankovic barely survived her opening match in the tournament. In the third set against Sofia Arvidsson of Sweden, Jankovic overcame a 5-1 deficit, then saved five match points in a tiebreaker. Jankovic had never advanced beyond the third round in five previous appearances at Key Biscayne. She'll next face Vera Zvonareva, who beat No. 13 Dinara Safina 7-5, 6
