Raducanu, ranked 42nd in the world, seemed hampered by a leg issue as Vekic cruised to the first set in less than half an hour.

The British number one rallied superbly to move a double break ahead in the second set, but twice failed to serve out victory - and could not convert two set points at 5-4.

Vekic, who is ranked 76th but is adept on the grass, is an experienced campaigner and held her nerve to level.

Both players looked to be tiring in a physical encounter, but Raducanu - backed by a vociferous home crowd - dug deep to force a tie-break.

Despite the defeat, Raducanu will take a lot of pride from an encouraging week on the British grass as she builds up towards Wimbledon.

Raducanu's season has been disrupted by a viral illness, meaning she was limited to only playing six matches from early February up to Queen's.

The ranking points she has earned in west London will push her up to the brink of the world's top 30, which could be enough to ensure she is seeded at the All England Club.

"I haven't really played much this season, but to think I have made two finals so far, which I haven't done in years, it has to be, in a way, celebrated," said Raducanu, who lost in the Cluj final in February.

"It's a good achievement for me and I'm proud of it."

Raducanu has enjoyed a productive week at Queen's, which is hosting the WTA event for the second year since returning after a 52-year hiatus.

The question mark coming into Sunday's final was in relation to her fitness.

Raducanu played two singles matches on Saturday because of rain disruption earlier in the week and slipped on the baseline during her quarter-final win over Kamilla Rakhimova.

She wore strapping on her left thigh during the second match - her semi-final win over American teenager Iva Jovic.

The taping was evident again when she walked out on to Andy Murray Arena to face Vekic and it immediately looked like her mobility was hampered.

As well as being unable to move as freely along the baseline, Raducanu was not getting as low in her groundstrokes as she had over the previous days.

Raducanu found herself 5-0 down after little over 20 minutes as Vekic produced an almost flawless returning game.

Raducanu asked for more treatment from the physio at that changeover, but then Vekic broke again to wrap up the opening set in less than half an hour.

Afterwards Raducanu said she felt the workload was "part" of her slow start.

"Of course, fatigue - you're not driving up as much for your serve, which is such a big thing on grass," she said.

"It's just been an amazing week, but it's also been a long week, waiting around and some long days."

At the start of the second set, Raducanu implored her team for more vocal encouragement - and the home crowd further increased their level of support.

Raducanu suddenly had more spring in her step and took her third break opportunity in the third game.

Raducanu was now able to elongate the rallies - which always felt like it would be the key to her success - as Vekic's level dropped.

Another break for 5-2 provided further hope to the home crowd.

Everyone could feel it was a different match - but could Raducanu make her dominance count?

Vekic particularly looked like she would not have relished a decider, but it was Raducanu who buckled first - perhaps through mental fatigue as much as physical.

After being unable to serve out, Raducanu's grip on the contest loosened and Vekic held her nerve to ensure a compelling second set did not lead to the match going the full distance.