Bernard Tomic has packed so many highs and lows into his short career that not much comes as a surprise any more, but winning a title in South America may just have done it.

On Sunday, the Australian defeated the Croat Ivo Karlovic to win the Claro Open Colombia in Bogota, the second ATP Tour trophy of his career and first away from his homeland. It is almost certainly no coincidence that one of the best moments of his career arrived just when he had started to be written off.

Tomic had failed to win back-to-back matches since January and had slipped out of the top 100 for the first time in three years. He also split from his management company IMG - its claims of a mutual decision rang distinctly hollow - which first signed him when he was 12.

Perhaps most importantly, for the first time in a long time, Australia was not relying on Tomic as their next big tennis hope. Nick Kyrgios' victory over Rafael Nadal and run to the Wimbledon quarter-finals, and the exuberant way the 19-year-old took to the big stage, made him an instant hero down under.

Kyrgios was presented as the anti-Tomic: mature beyond his years and ready to live up to his talent rather than flattering to deceive. Todd Woodbridge, the former doubles great who now works for Tennis Australia, told The Age: "The turning point in some ways for Bernard has been that he [Kyrgios] has come along and taken the limelight off him and I don't think he's really liked that too much. It's been a catalyst to turning around and having a really good result."

Tomic began the year by reaching the final in Sydney - he narrowly failed to retain the first title of his career - but was booed by his home supporters when he pulled out of his first-round match against Nadal at the Australian Open.

The 21-year-old took the unusual step of calling a press conference the following day with a doctor to show the severity of his injury and subsequently underwent hip surgery. He returned to action in Miami in March but lost 6-0, 6-1 to Jarkko Nieminen in 28 minutes: the shortest recorded professional tennis match in the Open era. From mid-January to July, Tomic won just four matches.

In Bogota, the Australian defeated four top-100 players one after another, including the defending champion Karlovic in the final. Taking on the Croat's monster serve at altitude is a fearsome task but Tomic was emotionally engaged in a way that too often has been missing and it was clear how much the title meant to him.

"It was a difficult match," he said. "I kept trying and believing in myself. Against him, if you stop believing and trying, he will beat you. It's my first tournament on hard courts [excluding Miami] since my surgeries in Australia. This title is huge and one I will always remember."

The victory lifted Tomic back up to 70 in the rankings but it comes too late to earn him a main-draw spot at next month's US Open. It means he will have to fight his way through qualifying unless Tennis Australia gives him the one wild card it has at its disposal. Kyrgios' ranking is high enough for him not to need one but there are plenty of other young candidates who may be considered more worthy recipients than Tomic given his lengthy list of misdemeanours.

Even if he misses out, his week in Bogota shows that it is not too late for Tomic to recapture the promise he showed as a teenager. It is easy to forget he is still only 21, and no-one younger has won an ATP Tour title this season.

He has pulled off a shock win. Tomic continuing to make positive headlines on the court: that really would be a surprise.