Kyrgios lost the match 7-6 7-6 to Cilic, who goes on to face Novak Djokovic in the tournament final.
The Serb has found his form on the grass having not lot a set all week including an impressive semifinal win today over the hot-handed Jeremy Chardy 7-6 (5), 6-4.
The former No. 1 has had more downs than ups, but this week in Queen's in back in his first ATP finals since winning Eastbourne last June.
After struggling in the first four months of the season due to a long break he was forced to take previous year, Djokovic has found his form in Rome, Paris and here in London, heading to Wimbledon as one of the favorites together with Roger Federer and Marin Cilic.More news: Spider-Man Silk Movie Spinoff in the Works By Sony
As the set sped towards another tiebreaker, the pressure was beginning to tell on Kyrgios as he yelled "I can't focus". It was not all gloom, of course, and he bridled when asked if winning a grand slam after a two-year drought would count among his best achievements: "It's what I'm playing for". I'm just glad to keep this going, and I don't want to celebrate too much.
"So for the first part of the match I was not really confident to actually hit the return", Djokovic said.
With temperatures heading into the high twenties, the delayed 2.45pm start - to accommodate England's World Cup match - saw Djokovic come quickly under pressure.
Cilic was on the verge of a third loss in the Queen's final when Djokovic held a match point in the second set. "I've played great tennis throughout this week and have another shot at the title", Cilic said. "Novak had such a great week, and it's really good to see him coming back so well, health-wise, playing at the top level", Cilic said.More news: Kane fires England to record 6-1 win against Panama
At 6-5 he forced three break points, and thought he had won the set on the second of them when Cilic fired a forehand wide, only for the call to be overturned by Hawk-eye.
The 23-year-old beat Andy Murray and Kyle Edmund recently and his run to the final in Stuttgart provided him with the ideal preparation ahead of the Wimbledon this summer. I played a lot of three-setters and a lot of tennis.
Kyrgios smashed 32 aces in a 7-6 (7/3), 6-7 (5/7), 6-3 second round victory at the Wimbledon warm-up on Thursday.
Rybarikova twice broke the Kvitova serve in the opening set and looked a strong candidate to claim the fifth WTA tour title of her career.More news: How Theresa May saw off another Brexit rebellion