The world number one beat China's Peng Shuai 7-5, 6-2 in the third round.
Unseeded Safarova will take on Russian Nadia Petrova, who beat holder Amelie Mauresmo of France in the other semi-final.
List of French Open women's singles champions:
Jelena Jankovic beat Czech Nicole Vaidisova while Ana Ivanovic upset 2006 runner-up Svetlana Kuznetsova.
Maria Sharapova showed there was no room for sentiment on Wednesday when she led a trio of Russian seeds into the second round of the French Open.
Ana Ivanovic fought back from a set to beat Svetlana Kuznetsova 3-6, 6-4, 7-6 in the final of the German Open.
World number one Justine Henin of Belgium fought back from the brink of defeat to reach the semi-finals of the German Open today, beating fifth-seeded Serbian Jelena Jankovic.
The Russian beat unseeded Katarina Srebotnik of Slovenia in the semi-finals of the Zurich Open.
The Slovak won her first title in five years when she beat Svetlana Kuznetsova in the Pacific Life Open final.
Justine Henin knocked out Swiss Patty Schnyder 3-6, 6-4, 7-5 to reach the Qatar Open semi-finals.
Amelie Mauresmo reached the Dubai Open final after Serbia's Jelena Jankovic retired through injury when trailing 6-2 on Friday.
The Belgian advanced to the German Open semi-finals with a 6-4, 7-6 victory over Russian Svetlana Kuznetsova.
The two will meet in the semi-final of the Dubai Open on Friday
The Swiss beat Russian Svetlana Kuznetsova in the 7-6, 6-3 in their quarter-final match the Rogers Cup.
Sania Mirza lost her women's singles and doubles matches at the Australia Open on Thursday.
The Belgian fifth seed thrashed Svetlana Kuznetsova 6-3, 6-1 in the semi-finals of the Sydney International.\n
Australian Open champion Marat Safin withdrew from the Hopman Cup in Perth due to a long-standing knee injury
Li Na upset Svetlana Kuznetsova 3-6, 6-2, 6-3 to become the first Chinese player to reach the singles fourth round at Wimbledon
Serena, a six-times champion in New York who is seeded 17th, will start her campaign against Polish world number 60 Magda Linette and could face Venus in the third round before a possible fourth-round showdown with Romanian top seed Halep.
Dinara Safina beat Maria Sharapova 7-5, 2-6, 7-5 in the fourth round of the French Open
The victory sent the Swiss through to the Italian Open final against 16th seed Dinara Safina.
Venus Williams beat Czech Lucie Safarova 6-1, 6-4 in the second round of the Italian Open
The second seeded Russian will play her doubles partner Anna-Lena Groenefeld, in the Family Circle Cup.
Top seed Nadia Petrova fired five aces in securing her 22nd victory of the year at the Amelia Island tournament.
Second seed Patty Schnyder was beaten by fifth-seeded Svetlana Kuznetsova of Russia in the quarter-finals.
Seven top 20 ranked players have already withdrawn from the event.
American qualifier Sachia Vickery completed an astonishing comeback to stun third seed Garbine Muguruza 2-6, 7-5, 6-1 in a second-round win at the BNP Paribas Open in California on Friday.
Maria Sharapova-led Russian brigade captured four of the round of 16 berths at the Australian Open on Friday
Hot favourites Russia will take on an under-strength France in the Fed Cup final after both nations completed 5-0 wins in the semis.
The world number two said she wants to concentrate on the 2005 season.
A summary of sports events and sports persons, who made news on Wednesday
The Belgian defeated Russia's Maria Kirilenko 6-2, 6-1 to reach the quarter-finals of the WTA tournament on Wednesday.