The last time John Millman faced Sam Querrey he wasn’t sure there was enough money in his account to pay for a flight home or if he had a future in tennis.

Shoulder surgery recovery had seen his ranking drop outside the top 1000 and the figure on his bank statement wasn’t much higher when he signed up for two Challenger Tour tournaments in California back in 2014.

On both occasions Millman lost to the giant American – a semi-final in Sacremento and a final in Tiburon – but crucially it was the start of his rise towards the top 100 – where he has largely remained since 2015.

On Saturday the pair will cross swords again for a place in the fourth round at Wimbledon.

The irony of the situation isn’t lost on world No.64 Millman – who’ll pocket $A318,000 if he qualifies for the second week for the first time – more than 10 times what he earned for reaching that decider in Tiburon.

“Sam was just outside the top 50, I reckon, and I was coming back from shoulder surgery,” Millman said.

“That trip actually for me to California was make or break.

“I only had a couple of grand left in the bank account but ended up going pretty well in some of those tournaments.

“I made quarters, semis and finals but Sam got the better of me in a semi and final.

“But … a bit of time’s past since then and hopefully I can turn that around.”

Millman will need replicate the form he showed at the US Open 10 months ago when he ousted Roger Federer against a player with outstanding Wimbledon pedigree.

The giant 31-year-old, who is ranked once place below the amiable Queenslander, has already sent world No.4 Dominic Thiem packing and in 2016 and 2017 he beat defending champions Novak Djokovic and Andy Murray.

Although the San Franciscan’s form has been well short of the performances that catapulted him to a career-high of 11th last year, Millman knows full well he’s got a big job on his hands.

“He’s a really good grasscourt player,” Millman said.

“He’s dangerous right now after making the final of Eastbourne and obviously he’s been dominant in his two matches (this week).

I’m going to have to keep really good quality on my ball.

“Sam is really looking to end points quite quickly because he wants that first shot at that ball, so I’m going to have to keep up my quality at the back of the court and take those little half chances that’ll come my way.

“If I can do that, I’ll be a chance.”