Del Potro won a coin toss and chose to receive and broke the first game. Period.
Commentators said just before the next match that Kei caught a flu.
He has not recovered from his right arm's injury either. These might explain the result.
BTW the pay view was awful. Bitrate is like 200 Kbps. No scoreboard. Commentators kept talking about their good old days or something no to do wth the match.