Djokovic was far superior to del Potro in the opening set, then dropped three consecutive games in the second to trail 4-3. But when Djokovic faced three break points in the following game, an epic that required 22 points to settle, he saved them all.
A series of missed forehands by del Potro in the tiebreaker put Djokovic back on course. He finished with a flourish, taking the last three games.
More to come...