Seeded No. 3 in the tournament, the 31-year-old Israeli came from behind to beat the fourth seed, Italy's Thomas Fabbiano 4-6, 6-4, 6-3.
The victory saw Sela climb 17 places in the ATP rankings to 81. There was more good news for Sela when the Wimbledon organisers informed him that he has been placed in the main draw of the tournament after two players ranked above him withdrew due to injury.
He was also told that he would have earned a wild card entry regardless following his triumph in Nottingham, as happened when he won the tournament in 2011.
This season has typified the inconsistency that has dogged Sela's career. He stormed into 2017 by winning the Canberra Challenger and reaching the second round of the Australian Open.
