Lopez has never gone past the quarterfinals at the All England Club but after winning his sixth ATP singles title the Spaniard will be one of the form players in Friday's draw.
For comparison, Andy Murray's early exit means he has played two competitive grass-court sets ahead of the third grand slam of the year while Lopez, having reached the final in Stuttgart last week, has 27.
He battled back from a set down and saved a match point in the deciding tie-break to win 4-6, 7-6 (7/2), 7-6 (10/8) against 2012 champion Cilic, to whom he lost in straight sets at the French Open last month.
"Wow, I cannot believe I have finally won this trophy," Lopez said.
"It was tough to put that match (against Grigor Dimitrov) away from my mind. I was serving for the match again and it was difficult to handle my nerves. I was waiting so long so I'm so happy today."