Serena Williams is one victory away from winning her fourth consecutive title this year - with the French Open only one week away.
The top-ranked American overcame an early break of her serve to ease past Romanian qualifier Simona Halep 6-3, 6-0 on Saturday and reach the Italian Open final, extending her career-best winning run to 23 matches.
Williams is coming off consecutive titles in Miami; Charleston, South Carolina; and Madrid last week.
In Sunday's final, Williams will face either third-seeded Victoria Azarenka or seventh-seeded Sara Errani, who were up next on center court on a perfect spring day at the Foro Italico.
In the men's semifinals, six-time champion Rafael Nadal will face sixth-seeded Tomas Berdych and Roger Federer plays 36th-ranked Benoit Paire of France.
Williams' only title at this clay-court event came in 2002, when she beat Justine Henin in the final. That was also the year she won her only French Open title. Last year in Paris, Williams lost in the opening round of a major for the first time, falling to 111th-ranked Virginie Razzano of France.
The tournament at Roland Garros starts next Sunday.
Williams has twice won 21 in a row before, although both of those runs came a decade ago, in 2002 and 2003.
Martina Navratilova established the longest women's win run in the Open Era at 74 matches in 1984.
At 31, Williams is back at the top of her game after missing 11 months in 2010 and 2011 with a right foot injury and a pulmonary embolism.
The 64th-ranked Halep entered with an impressive run herself, having beaten former top-10 player Daniela Hantuchova to qualify, then 2009 French Open champion Svetlana Kuznetsova in the first round. That was followed in succession by fourth-seeded Agnieszka Radwanksa, 13th-seeded Roberta Vinci and two-time Rome winner Jelena Jankovic.
Solid off both sides and an agile mover, the 2008 French Open girls champion took a set off Williams in their only previous meeting in the second round of Wimbledon two years ago. Halep tested Williams again at the start of this match, angling baseline shots to the corners to force the 15-time Grand Slam winner into errors.
Halep broke to take a 2-1 lead in the first set, but Williams broke right back and cruised from there as she gained the measure of her opponent and began to win the longer rallies.