Qureshi was playing in the main draw of an ATP tournament for the first time this year after battling through qualifying on the Halle grass.
The 27-year-old from Lahore, ranked outside the top 300 but a grasscourt specialist, edged the first set 10-8 on the tie-break and went on to complete victory in one hour 38 minutes.
Roger Federer, the world number one and top seed, withdrew from the tournament on Monday, citing fatigue after his French Open final defeat by Rafael Nadal the day before.
