Recent matches have sparked speculation about Djokovic's motivation. His losses at Qatar and Indian Wells to Matteo Berrettini and Botic van de Zandschulp raised eyebrows among fans and analysts.

Novak Djokovic cruised into the quarter-finals of the Miami Open on Tuesday with a 6-2, 6-2 win over Italian Lorenzo Musetti in one hour 22 minutes. Musetti, the 15th seed from Tuscany, got off to a ...