World number six Juan Martin Del Potro has suffered an injury scare before the French Open, retiring from his Italian Open match with David Goffin.
Belgium's Goffin was leading 6-2 4-5 when Del Potro, who had just missed a set point, retired with a groin injury.
World number one Rafael Nadal cruised into the last eight with a 6-4 6-1 win over Canadian teenager Denis Shapovalov.
Croatian fourth seed Marin Cilic won 6-3 6-4 against France's Benoit Paire.
The French Open, the second Grand Slam of the year, begins on 27 May at Roland Garros in Paris.