Scrutinise the past 12 months and it would take a very brave observer not to include Japan’s Shintaro Mochizuki on a list of players to keep close tabs on during the coming years.

After all, 2019 has proven something of a breakthrough period for the teenager, who became the first Japanese boy to contest a Junior Grand Slam final when he reached the business end of the Junior Championships at Wimbledon in July.

He took that accolade a step further by defeating Spain’s Carlos Gimeno Valero and lifting silverware, while he spearheaded Japan’s victory march at September’s Junior Davis Cup by BNP Paribas Finals in Orlando.

Such progress, which also included a semi-final appearance at the Roland Garros Junior Championships, is likely to see Mochizuki feature increasingly within the game’s professional ranks during 2020.

Given the significant achievements already accomplished by the 16-year-old, it would be a fair assumption that his career path has been set in stone for some time. Such as hunch, however, would be misguided.

Not so long ago, Mochizuki, who is a New York Yankees fan given the presence of Japanese pitcher Masahiro Tanaka on their roster, faced a potentially career-defining decision over whether to pursue tennis as his primary sport.

“I was going to quit tennis when I was nine or 10 years old and change to baseball,” Mochizuki told www.itftennis.com. “My parents didn’t push me to play tennis but I played a lot with them and my coaches so, in the end, I couldn’t quit.

“I kept playing tennis and have kept trying my best. I enjoyed baseball and used to play a lot, that and swimming although that was just for fun with my friends. I still play a little baseball, but not seriously. I’m so glad I stuck with tennis.”

Delve into his past association with the sport and perhaps the pendulum was always likely to swing in favour of tennis, to which Mochizuki was introduced at the age of three by his father, who is a taxi driver.

The biggest clue may well be the pictorial evidence within the family home of Mochizuki, at the age of just one, with a tennis racquet in hand.

“My dad was a tennis coach and he loved tennis,” said Mochizuki. “One day he let me play and immediately I loved it too. From there I started playing seriously and I’ve never stopped.

“My parents have pictures of me at one year old and I am holding a racquet. They told me that I held my racquet for something like three hours a day. I obviously don’t remember doing that but they were always convinced I was going to love tennis.”

His affection and appetite for the game led to Mochizuki leaving Japan at the age of 12 and heading to the IMG Academy in Bradenton, Florida. “I was so scared,” he revealed. “I knew very little and couldn’t speak English.

“But by living and training in America I have become stronger. I am so much stronger right now than when I was living in Japan.”

Despite the acknowledgement that moving stateside has been hugely beneficial in terms of his development, hankerings for home remain. “For tennis, I love it and it is so much better to train there, but I miss Japanese food,” he says.

Certain other observations suggest Mochizuki, who listens to J-pop, watches Youtube for up to five hours a day and loves to sing, remains steeped in the culture of his homeland. He adds: “I am different. I practice a lot. Americans practice for just an hour a day, whereas I am still Japanese.”

But whatever hurdles Mochizuki has had to clear, he will head into 2020 with a Junior Grand Slam and Junior Davis Cup crown on his CV. He was very much in the running to close the year as the top-ranked boy on the planet but in the end finished fourth behind Argentina's Thiago Agustin Tirante and fellow major winners Holger Vitus Nodskov Rune of Denmark and Czech Jonas Forejtek.

Despite missing out on the rankings summit, there is little doubt that 2019 has been a progressive year and one which has fuelled an ambition to enjoy a prosperous and trophy-laden future.

“It was an amazing year, the best of my life,” said Mochizuki, who finished fourth at October’s ITF Junior Finals in Chengdu. “There was plenty of hard work and it has paid off, but I still lost many matches and tournaments. I know I must continue working hard every day of every year.

“It was great experience for me to win the boys’ title at Wimbledon, although at the time I didn’t really know what was happening out there, and Junior Davis Cup. Those wins have given me a burning desire to do the same at senior level.

“I’ve seen pros playing at Grand Slams and I believe I can play and win those sorts of matches in the future. It is step by step but my dream and ultimate goal is to be No. 1 in the world.”