Rafael Nadal will keep the No. 1 ranking for at least another week following an efficient 6-1, 6-3 win over Croatia’s Marin Cilic in the Italian Open quarter-finals yesterday.

Nadal was at risk of losing the top spot to Novak Djokovic if he failed to reach the semifinals of this clay-court tournament, which the Spaniard has won for five of the last six years.

Nadal played much sharper than in his previous two matches when he was affected by a virus. His semi-final opponent will be either seventh-seeded Tomas Berdych or 16th-seeded Richard Gasquet, who eliminated Roger Federer on Thursday.

Nadal didn’t face any break points on another perfectly clear day at the Foro Italico.

In the other half of the draw, Andy Murray overcame a slow start to beat German opponent Florian Mayer 1-6, 6-1, 6-1 and become the first British man to reach the Rome semi-finals since 1932.

In women’s action, top-ranked Caroline Wozniacki overcame two-time Rome champion Jelena Jankovic 6-3, 1-6, 6-3 and will next face either third-seeded Victoria Azarenka or seventh-seeded Maria Sharapova.

Australian Open runner-up Li Na of China beat Greta Arn of Hungary 6-3, 6-1 and will face sixth-seeded Sam Stosur for a spot in the final.

Stosur got a measure of revenge on Francesca Schiavone by beating the Italian 6-2, 6-4 in a rematch of last year’s Roland Garros final. Stosur never dropped her serve and faced only one break point.