Frances Tiafoe (USA)

Last week’s ranking: 91
Current ranking: 61

The American made the biggest breakthrough of his fledgling career at last week’s Delray Beach Open. The charismatic 20-year-old defeated Peter Gojowczyk to snap up a maiden ATP title – and banked 250 ranking points in the process.

Tiafoe, the youngest American title winner since Andy Roddick in 2002, had struggled to find his best form in the early stages of the season, but he showcased his undoubted talent in Florida.

The American is now ranked No.61 – just one place below his highest ever postion – and it’s unlikely to be too long before he takes his place inside the Top 50.

Diego Schwartzman (ARG)

Last week’s ranking: 23
Current ranking: 18 (Career-high)

The gritty Argentine celebrated his second clay-court title success in Rio de Janeiro on Sunday.

The 25-year-old, who has to graft for every point he wins, dominated Fernando Verdasco 6-2 6-3 to net silverware on South American soil for the first time. It’s also his first triumph at ATP 500 level, and his continued improvement is testament to his work ethic.

Schwartzman was once unsure whether a career in tennis was a viable option due to his lack of height, but he is thriving as the perennial underdog.

His victory in Brazil’s second biggest city had earned him a spot inside the Top 20 for the first time. The plucky Argentine has already overachieved in his eight-year career, and he has not even entered his peak yet.

Karen Khachanov (RUS)

Last week’s ranking: 47
Current ranking: 41

The understated Russian has the attributes to prosper indoors, and he departed the Marseille Open with a trophy under his arm.

It had been a low-key start to the campaign for Khachanov, but he found his groove in the south of France. Excellent victories over Tomas Berdych and Lucas Pouille en route to his second ATP title further highlighted his potential.

He is the No.2 ranked Russian and sits just nine places and 198 points behind his compatriot Andrey Rublev. The 21-year-old remains a fair distance from his career-best ranking of No.29, but he is back on track after a sticky spell.

Fernando Verdasco (ESP)

Last week’s ranking: 40
Current ranking: 27

The evergreen Spaniard dazzled on the red dirt at the Rio Open.

Verdasco joined forces with David Marrero to bag the team game title in Brazil, but Schwartzman denied him a dream double by prevailing in the singles final.

The Spaniard’s form continues to fluctuate, however he has lost none of his shotmaking capabilities. His forehand, despite his advancing years, remains a sight to behold and few players can match the veteran for entertainment value.

The 34-year-old is unlikely to remain at such a lofty ranking position for long. He reached the final of the Dubai Duty Free Tennis Championships last year and will need to have a productive week in Acapulco if he wishes to maintain his place inside the Top 30.