The Brit, who won three qualifying rounds to make the main draw for the first time in his career, was beaten 4-6 6-4 6-2 6-4 on Monday.
Despite being knocked out of the tournament in the opening round, Ward is pleased with how he played against the Spanish world number 19.
"I thought I played really well throughout the whole match," he told the ATP's official website. "I fought hard, got back into the match, and, again, had a couple of chances in the fourth [set].
"He's one of the toughest players to play on clay in the world. I put him up there in the top five of the last 10 years."
Waiting for Robredo in the second round is France's Kenny de Schepper.