Nadal in quarters as Porto, Keys withdraw from Italian Open

Ukraine's Elina Svitolina serves to Russia's Darja Kasatkina during Rome's WTA Tennis Open tournament on Thursday.

Seven-time champion Rafael Nadal methodically wore down Denis Shapovalov in a 6-4, 6-1 win to reach the Italian Open quarterfinals and gain a measure of revenge against the Canadian teenager.

Shapovalov saved eight break points in his opening two service games before finally dropping his serve midway through the first set on Thursday.

Shapovalov, who is ranked a career-high No. 29 this week, stunned Nadal in the third round in Montreal last year to deny the Spaniard a chance at regaining the No. 1 ranking.

Nadal is also attempting to regain the top spot this week. He'll replace Roger Federer at No. 1 if he wins an eighth Rome title.

Nadal, who hasn't won the Italian Open since 2013, will next face Fabio Fognini, who beat Peter Gojowczyk 6-4, 6-4 to reach his first quarterfinal in 11 appearances at his home tournament.

The temperamental Fognini slammed his racket midway through the second set and received a warning from the chair umpire but otherwise held his composure to follow up an impressive win over Dominic Thiem a day earlier.

Also, ninth-seeded David Goffin was leading 6-2, 4-5 when Juan Martin del Potro retired because of a groin injury; and 10th-seeded Pablo Carreno Busta beat Aljaz Bedene 6-4, 6-7 (3), 6-2.

In the women's tournament, Simona Halep's hold on the No. 1 ranking received a boost when American opponent Madison Keys withdrew from their match due to a right rib injury.

Halep needed to reach the quarterfinals and progress further than No. 2 Caroline Wozniacki to hold onto the top spot, and she accomplished the first task.

Wozniacki was facing 15th-seeded Anastasija Sevastova in a late match on the red clay of the Foro Italico. The winner will play Anett Kontaveit.

Kontaveit ousted 1999 Rome champion Venus Williams 6-2, 7-6 (3).

Keys also withdrew from the doubles competition, where she was partnered with Williams.

Last year in Rome, Halep rolled her ankle in the final and lost a lead and the championship to Elina Svitolina.

Svitolina also reached the quarterfinals, overcoming a poor start to beat 14th-seeded Daria Kasatkina 0-6, 6-3, 6-2. She'll next face former No. 1 Angelique Kerber, who routed Maria Sakkari of Greece 6-1, 6-1.

This is the last major warmup for the French Open, which starts in 10 days.

Jelena Ostapenko, who is preparing to defend her title at Roland Garros, rallied past Johanna Konta 2-6, 6-3, 6-4 and will meet either three-time Rome champion Maria Sharapova or Daria Gavrilova.