Ivo Karlovic approaches the practice desk at the Ecuador Open, writes his name with a blue pen on the sheet to book a court from 11.30-1.30, and specifies that he is looking for a practice partner.

He goes back to the hotel to sleep. Maybe when he returns to the Club Jacarandá, someone will have signed up to be his practice partner, so he can play some points. But when he gets back and checks the sheet, no one has written their name down next to his. In other columns he reads: Bellucci + Monteiro, Estrella + Zampieri, Cerratani + Oswald.

All the practice courts at 11.30 have at least two players booked in. All except for the court of the top seed in Quito. For the third time during his stay at the ATP World Tour 250 tournament – and for the thousandth time during his 17-year career – Karlovic must practise alone with his coach, the Serbian Petar Popovic.

He asks for three tubes of balls and walks towards practice court No. 7, while fans stare at him open-mouthed. Being 6’11” will cause that reaction. Once on the court, Ivo starts to warm up and Popovic gets on with his own routine, which he had when he competed on the ATP World Tour before retiring in 2008 at the age of 26.

“It’s not that often that I get to practise with another player,” explains Karlovic. “They don’t really like to practise with me, but I don’t have a problem with that. I have to see my coach almost every day on the other side of the net.” Popovic laughs at his answer. They usually joke about this.

Almost no-one likes to hit with Karlovic because of his flat forehand, slice backhand and his lethal serve, which holds the record for more than 11,000 aces. While the majority of players look for consistency in points to build confidence, Karlovic tries to finish the points as quickly as possible. His style is uncomfortable. “They aren’t used to my game and they can’t find a rhythm.

“But I think this situation is an advantage,” adds Karlovic, a winner of eight ATP World Tour titles and currently No. 18 in the Emirates ATP Rankings. “The less they practise with me, the less likely they are to get used to my game. I like having a unique playing style. The good thing about practising with Petar is that I can do specific work that I need to do.”

Popovic, three years younger than Karlovic, isn’t one of those coaches that leans against a wall to watch and observe a practice session. He sweats as much as or more than his player. “I understand the other players not practising with Ivo because there is zero rhythm playing against him. So it is up to me to be fit enough to practise with him. On holiday I practise three times a week and go to the gym.” It’s not for no reason. Every day, he waits to receive serves faster than 200 kilometres per hour.

The practice situation has strengthened the relationship between them. Karlovic doesn’t know if one day someone is going to write their name next to his on the practice schedule, but the company of Popovic is a certainty. “Above everything, Petar is a friend. Then after that he is someone whom I’ve worked with the past three years. We spend a lot of time together and we get on very well. He is very funny.”

“Our relationship is fun,” explains Popovic. “Sometimes I tell him: ‘Take this, do this.’ And he says: ‘Yes, dad!’ It’s funny because he is older and taller than me. We always find a way to laugh at ourselves. It’s better to be like this because over the course of a year I see more of Ivo than my wife and children!”

Jim Courier was bouncing the ball ahead of his fourth match point, his ever-present white-brimmed cap was pulled low and tight over his brow. A strong serve down the line gave Courier the initiative to attack the net and the resulting backhand volley landed out of the reach of Derrick Rostagno to complete a 4-6, 6-3, 6-2 semi-final victory. At that very moment, on 8 February 1992, in the illuminated downtown auditorium in San Francisco, the 21-year-old American was assured of becoming the 10th player in Emirates ATP Rankings history (since 1973) to reach the summit of men’s professional tennis. He dropped to his knees and raised his hands to the sky.

It wasn’t immediately obvious growing up that Courier would become a champion as he pummelled groundstrokes against the wall of a handball court in Dade City, Florida. “Tennis was a fun thing to do with my family and I didn’t dream too far in the future in the early days,” Courier told ATPWorldTour.com. “We watched some tennis on television, but it wasn’t something that I had an early idea of pursuing as a profession. I wasn’t one of those kids pretending to hit a shot to “Win Wimbledon” on the wall like you hear about.”

His parents, Jim Sr. and Linda, always ensured that his brother Kris, and sister, Audra, had equal opportunities. ”Becoming No. 1 was an amazing feat, but it was never the reason I worked hard or the reason my family had made sacrifices on my behalf,” said Courier. “I worked hard from an early age because I had been taught to do so and I wanted to see how good I could be.”

Thoughtful and intense, it was Courier’s tenacity, tremendous work ethic and will to win that ensured he maximised his talent to ultimately usurp Stefan Edberg at No. 1 on 10 February 1992.

Having enlisted the services of Jose Higueras, then working with the U.S. Tennis Association player development program, in November 1990, Courier started the 1991 season ranked at No. 25. Higueras began to address mental and physical aspects and Courier went on to grind his way to No. 2 by winning four titles – including 1991 Roland Garros and the 1992 Australian Open, reaching the ATP Finals and the semi-finals of six other tournaments. “I didn’t start to think too much about reaching No. 1 until it was within my grasp,” admitted Courier. “At the end of 1991, I knew I had a chance to get there if I had a good start to ‘92 and that was exactly what happened with a win at the Australian Open [beating Edberg], which put me on the precipice.”

Courier earned tough wins over a trio of Australians – Mark Woodforde, Jason Stoltenberg and Wally Masur – in San Francisco, as the weight of what he was trying to achieve begun to hang heavily. “I was stressed out about it,” said Courier. “I was very aware of the situation. I just wanted to get there for one week. Derrick was a tricky, dangerous fast-court player and I had to grind my way through that match to get to No. 1. I was battling Derrick as well as the ranking and it was as much of a relief as it was a thrill to win the last point and get to the top of the rankings mountain…

“I remember going down to my knees, saying to myself: ‘This is it, this is the moment [and] they can never take it away from me.’”

Courier was the first American at World No. 1 in six-and-a-half years, following in the footsteps of John McEnroe, who was last there on 26 August 1985. Courier idolised Bjorn Borg as a youngster, admitting, “I tried to emulate his game style and attitude and failed miserably at both, but it worked out in the end.”

Although Courier lost to Michael Chang the next day, in the San Francisco final, he experienced a novel adventure as the Florida-based ATP computer officially listed him as the new No. 1 in the Emirates ATP Rankings. Having missed an overnight flight to London, Courier caught a red-eye to New York in order to fly onto the English capital by Concorde, and then onto Brussels to fulfil a corporate commitment and play at his next tournament.

”We were on Concorde, heading to the runway but we backed up, the nose wheel wouldn’t turn and so the flight was cancelled,” remembers Courier. “So I spent my first full day at the No. 1 player ordering pizza, sitting in an airport lounge with strangers, with my agent and girlfriend.”

Aged 21 and five months, Courier’s hold on No. 1 was never secure and in the space of 18 months he had exchanged the position with Edberg and his fellow American Pete Sampras. “I enjoyed the battle to get to and try to stay at No. 1, as well as simply trying to get better as a player at the same time. It was a wonderful experience.” Courier spent a total of 58 weeks at No. 1, over four different stints, and eventually retired in May 2000 with 23 titles – including four majors and five ATP World Tour Masters 1000 crowns.

”There are a few things that are mentioned when I am introduced at an event and No. 1 is something that is part of my bio,” says Courier.

“It’s a badge of honour I am proud to wear.”

Third seed Paolo Lorenzi continued his solid form in Quito on Thursday at the Ecuador Open, moving into the quarter-finals with a 6-4, 6-4 win over Matthew Ebden.

The Italian required just a single break of serve in each set and didn’t face any break points. Lorenzi has reached at least the quarter-finals in all three of his appearances in Quito, with his best result being a semi-final finish last year.

Next up for Lorenzi is Rajeev Ram, who reached his first ATP World Tour quarter-final on clay by defeating Nicolas Kicker 7-6(5), 6-3. The third seed leads their FedEx ATP Head2Head rivalry 1-0, prevailing on the indoor courts of Vienna in October 2015.