"We're both coming off injuries but I think it will be a really good match," del Potro told reporters. "I'm going to play my best tennis against Roger."
On Wednesday, del Potro produced some of the tennis that had helped him to number four in the world before he was struck by a succession of injuries, notably to his wrists.
He did not lose a service game and blitzed through the opening set but failed to close the match in the 10th game of the second set where he had match point.
In the tiebreak he won three of the last four points to seal his second round spot after 87 minutes.
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In earlier action, Britain's Kyle Edmund survived a tight clash with Czech Jiri Vesely 6-4 5-7 7-6(6) to earn a meeting with world number one Novak Djokovic, who won last week's tournament in Indian Wells.
(Writing by Jahmal Corner in Los Angeles; Editing by Greg Stutchbury)
