Murray's coach since 2016, Delgado has been through the wringer with the former world No.1, who is currently ramping up preparations for the US Open after receiving a wildcard entry.
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The Scot ascended to the summit of the global rankings after a thrilling 2016 but has since struggled with a long-term hip injury that saw him undergo two surgeries in 2018 and 2019.
Murray, 33, recently competed in the Battle of the Brits and Delgado says the desire to duel it out with Novak Djokovic, Rafael Nadal and Roger Federer still burns as brightly as ever ahead of Flushing Meadows at the end of the month.
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"It's been frustrating - it's lingered for a while but at the end of the day he wants to be out there competing against the best players in the world and doing what he loves," the 43-year-old said.
"He's still motivated, of course he is - he's super determined, absolutely, and that's the goal, no doubt, to get back competing against the best players again.
"And his team feel exactly the same way - that's what we're working hard towards, and he works so hard with all his gym work and rehab work that he does.
"At the end of last year he finished off the year really well by winning in Antwerp, so that was great, and then this year - for different reasons - we haven't been able to get the tournaments in.
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"Hopefully we can get back out there, and we're just looking forward to just getting out there and competing."
Murray was crowned king of the European Open in Antwerp in October amid emotional scenes after enduring a nightmare couple of years with injuries.
The current world No.129 announced his potential desire to retire at the Australian Open in 2019, later withdrawing from the competition owing to hip pain and going under the knife for a second time at the end of January.
He's since made a steady return to competing among the worlds best, dabbling in doubles alongside the likes of Feliciano Lopez, Serena Williams and brother Jamie.
Image credit: Getty Images
And that triumph on the Belgian courts soon followed, as Murray toppled long-term rival and three-time Grand Slam champion Stanislas Wawrinka in the final.
A hat-trick of Grand Slams for Murray have cemented his legacy as a British sporting great but Delgado says it's a source of regret that the 46-time title winner could have won more.
"He was obviously No.1 in the world at the time, so do I think he would have won more since he's been injured? Yes, but obviously we don't know for sure, do we?" he added.
"It's tough to say [what would have happened without the injuries] - a year before he got injured he'd won Wimbledon and the Olympics in 2016 and finished world No.1.
"So he would have been in the running for them [Grand Slams], for sure.
"He's been working really hard and trying to get himself as ready as possible for the competition."
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Delgado was speaking at Classic Week of the inaugural UK Pro Series, a unique new format he helped devise that culminates in 24 of the country's leading stars descending on Weybridge after five individual qualifying weeks.
Widely-billed as the â€˜Premier League of British tennis', a glittering array of talent are competing at St. George's Hill Lawn Tennis Club including Harriet Dart, Jodie Burrage and Eden Silva in the women's draw and James Ward, Arthur Fery and Liam Broady in the men's.
Delgado and Murray fly out to New York this week and the coach says he's excited about the prospect of Murray being back out on court behind closed doors.
"The US Open's going to be very different, but unique as well - it'll be fun to see how it all works, so we'll see how it goes," he said.
"We're looking forward to getting out there and playing matches as he hasn't played that many matches.
"He obviously played in the Battle of the Brits, but then we've had the Covid stuff, while he also pulled out of the Australian Open before.
"I think we're looking forward to just getting out there and competing."