The victory, though, was achieved after the Argentine retired mid-way through the contest.
After the No 78-ranked Indian won the first set 7-6(3) in 67 minutes, the second seeded Del Potro took a medical time-out, complaining of pain in his left wrist. He was unable to continue and conceded the match.
Somdev had lost 4-6, 4-6 to Del Potro in the pre-quarter-final last year in the same tournament.
This is his first victory over a top five-ranked player.
He was well-prepared coming into the tournament, having won the Delhi Challenger on Sunday and reached the semi-finals of the Chennai and Kolkata Challengers in the preceding weeks.
The Indian traded a break before pushing the match into the tie-breaker, in which he kept attacking the Del Potro’s backhand.
Image: Juan Martin Del Potro of Argentina (right) shakes hands with Somdev Devvarman of India after retiring with a left wrist injury during the men's singles match at the ATP Dubai Tennis Championships.
Photograph: Faisal Al Nasser/Reuters
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