Lopez has never gone past the quarter-finals 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.
But that was on clay and this on grass, Lopez's favourite surface, where the world number 32's bending left-handed serve and sizzling slice backhand can be exploited to the full.
For Cilic, this was a surprise loss but he too will head to SW19 full of confidence after an excellent week, which had seen the likes of Murray, Milos Raonic and Stan Wawrinka all falter in the first round.
At 35 years old, Lopez is enjoying something of an Indian summer in his career and after knocking out world number three Wawrinka on Tuesday, he can add Cilic to an impressive list of scalps.
He spurned a match point before losing to Grigor Dimitrov in the final three years ago but this time held firm to secure the trophy.
"I think it's the best week of my career," Lopez said.
"To win this tournament at this stage of my career, this is so amazing. I was waiting so long to win this title. Queen's is the best, I think outside of the grand slams, this is one of the most special tournaments."
Lopez battled back from a set down against Cilic and saved a match point in the deciding tie-break before sealing the title and winner's cheque for 395,690 euros (£347,700).
"I think beating four top 10 players in the same week, this is pretty amazing," Lopez said.
"The fact I have played these guys this week and been able to beat them, it gives me even more confidence, no? Sometimes the draw becomes open after some of the top guys lose but in my case, it was not like this.
"From the very beginning I had the best players in the draw. So that gives me a lot of energy for the rest of the season."
Lopez will be a dangerous prospect for any of the favourites at Wimbledon after a week in which Andy Murray, Milos Raonic and Wawrinka all lost in the first round.
"Tennis is a unique sport where anything can happen," Lopez said.
"It is true that I'm going into Wimbledon with a lot of confidence, probably this is the Wimbledon that I feel more confident going into.
"But next week, the draw has to be done and then I hope I can still play in the same way, no?"
Lopez paid tribute to Cilic too, whom he believes should now be considered among the world's "top three" on grass, behind only Murray and Roger Federer.
Cilic blew a two-set lead and three match points against Federer at Wimbledon last year but the Croatian looks primed for a renewed challenge at SW19.
"Looking on the whole week, it was great tennis for me," Cilic said.
"I have to say maybe one of the best grass court tournaments for me overall throughout my career, looking at the consistency of the game.
"I lost my serve only once during whole week, which is amazing, considering last week I didn't lose serve (at the Ricoh Open) in the Netherlands either. That makes it even better."
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