In the early part of the season, Clijsters and Sugiyama won three titles on hard courts. However, they did not win any big titles through May, losing in the Australian Open quarterfinals to the Williams sisters and finishing runners-up at their first two Tier I finals. They entered the French Open and Wimbledon and made it to the finals at both events. Clijsters and Sugiyama defeated the top seeds Ruano Pascual and Suarez in both finals for Clijsters's first two Grand Slam tournament titles. The French Open final was a tighter match, ending 9–7 in the third set. Despite these titles, the duo remained behind Ruano Pascual and Suarez in the rankings until August when Clijsters became world No. 1. She held the top ranking for four non-consecutive weeks. The pair were the top seeds at the US Open, but withdrew in the second round due to rain delaying Sugiyama's fourth round singles match for three days. They ended the season by finishing runners-up to Ruano Pascual and Suarez at the WTA Tour Championships. Despite Clijsters's success in 2003, she seldom played doubles during the rest of her career.