Cilic is guaranteed to be at least No. 6 in the rankings, which is a career high, after dealing Muller a first loss of the grass-court season following the left-hander's title win in Netherlands last week.
"I thought that at the end of the tiebreak after losing match points I wouldn't make it but I managed to do it".
Two 35-year-old tennis players have proved the old cliche that age is just a number once and for all - all within a matter of a few hours.
But Cilic is confident the dominant form he showed for the rest of the tournament will stand him in good stead at Wimbledon, where the former US Open champion has lost in the quarter-finals three years in a row.
"Looking at the whole week, it was great tennis for me", Cilic said. Definitely hoping that I can go further than the last three years. "That's where my focus is going to be".
"Considering the results of the best players in the world, it is true that it is probably the most open Wimbledon in the last 10 years, I will say", Lopez said, referencing the struggles of Wimbledon champion and world number one Andy Murray and three-time victor Novak Djokovic.
Roger Federer will arrive as tournament favourite after maintaining his superb run by winning the Halle title yesterday, but French Open champion Rafael Nadal hasn't thrived at Wimbledon for several years.
"But next week, you know, the draw has to be done".
'Definitely he's going to be playing really well, and, you know, he's feeling at home in Wimbledon.
An agitated Cilic held on for another tie-break and this time it was neck and neck, Lopez whipping away a winning forehand off one foot for a 5-4 lead only for Cilic to pat a passing shot inside the baseline for 5-5.
It took almost nine sets this week for Lopez to lose his serve, helping Dimitrov take the semifinal to a deciding set.
Lopez, ranked 32nd, has now reached back to back grass-court finals after following his defeat in Stuttgart with victory in west London.
"I think beating four top 10 players in the same week, this is pretty awesome", Lopez said.
Willis starts against Martin, who has never made the main draw at Wimbledon but beat world number 15 Lucas Pouille in straight sets at the French Open past year.
'But yeah, definitely I would say the top guys haven't played the best of their best, so definitely it opens up a gap for a lot of guys'. "I knew it would be hard today but I've played some of my best tennis all week".