Tennis coach Jonny Carmichael remembers thinking the five-year-old he had just met on the courts of Pelican Park in Hull was a bit annoying.

"He was one of these kids that just picked up a racket and could get a rally of 100," says Carmichael. "Imagine being someone who is that good at something immediately."

Fourteen years later and the small boy with the natural flair is about to make his Wimbledon debut.

Paul Jubb's story is not like any other in British tennis. Orphaned before he ever picked up a racket, Jubb was brought up by his grandmother Val round the corner from Pelican Park.

The courts quickly became his second home and, under the tutelage of Carmichael, who was just starting his own coaching journey, Jubb blossomed.

"What really stood out about him was he's such a good mover," Carmichael tells Press Association Sport. "Not just quick but quick and balanced and just so athletic."

Jubb had no background in the sport and he only found Pelican Park because a colleague of Carmichael's carried out coaching sessions at his primary school.

Carmichael believes Jubb's modest means have given him an edge on court, but they also presented a serious obstacle to his progress in a sport that is notoriously expensive.

"You can see those players who are only good because they've got the means to be good," says Carmichael. "Tennis is a difficult sport to learn, you need to put a lot of time into it, and that costs money.

"Obviously there's a lot of good players in this country but you tend not to get those champions because they're a bit wet. Whereas he had all the natural ability, he just didn't have the means to get around."

Carmichael's solution was to dig into his own pocket.

"I used to teach him for free and take him around places because I liked him, he was just a good kid. Also I was learning as a coach – great, I've got a little guinea pig here.

"As time went on I just wanted to help him reach his potential. I never thought it was going to be anywhere near this level."

When Jubb won the national under-16 title in 2015, Carmichael began to realise his charge was outgrowing Hull, and two-and-a-half years ago the teenager headed off to the University of South Carolina.

He was given a 50 per cent scholarship, which left a significant shortfall, but Jubb and Carmichael had saved up Lawn Tennis Association funding that covered the rest.

Jubb impressed his coaches and teachers so much in his first year that he was subsequently given a full scholarship, enabling him to finish his studies.

And he proved that investment was more than justified in May when he became the first British player to win the prestigious National Collegiate Athletic Association men's singles title.

The fact that Jubb would have earned a wild card for the US Open had he been American led to a flurry of calls for him to be given a chance at Wimbledon, and he boosted his case further with several impressive wins at the grass-court tournaments in Nottingham and Ilkley.

When Wimbledon announced last Wednesday that four men had been awarded wild cards, Jubb's name was among them.

"We thought he was going to get a qualifying wild card," says Carmichael. "And then after his win on Tuesday a guy from the LTA said to him unofficially, 'they're going to give you a main-draw wild card'.

"I drove back to Hull on Tuesday night, I rang my wife, I rang my mum, I was like, 'you can't tell anybody, but this is happening'. It was just unbelievable."

The speed of Jubb's rise to national and international prominence has certainly been dramatic, and Carmichael is struggling to get his head around the company with which the 19-year-old will be keeping.

"The thought he might play Nadal or Federer or Djokovic, I can't even comprehend that," says Carmichael.

"If Paul Jubb, a little rat from east Hull, walks on to Centre Court, I can't even imagine it. We're going to be in the players' lounge, the locker room. I'm just going to have to pretend I don't know who anyone is. 'What's your name? Oh, Roger'. We're both going to play it really cool I think."

As for where Jubb can get to in tennis, Carmichael sees no reason why anything should be beyond the boy from Pelican Park.

"He always seems to manage to reach his goal. I don't really know what his limits are but I always believe he can keep improving."