American tennis star Tristan Boyer kicked off at chair umpire Nick Flentie after losing in the first round of the San Diego Open on Monday.

The 23-year-old was down one set against Alex Bolt and fighting to stay in the tournament during a second-set tiebreak. With the scores level at 4-4, Flentie pulled Boyer up for a time violation and made a marginal 'out' call against him in the proceeding rally.

With a deep breath, Boyer kept his cool at the time but completely erupted after hitting into the net on Bolt's match point.

Within a split second, Boyer screamed out at the top of his lungs and began repeatedly smashing his racket into the ground. With the racket a crumpled mess, the American jogged to the net and shook the hand of his opponent before unloading on the umpire.

"Unbelievable," he ranted. "It's ridiculous. You guys can't do one thing right! God, it p***es me off. God, it's frustrating. All over the place, horrendous calls. Horrendous calls!

"What are you doing giving me a time violation?! There are three people here. There are three people here watching me! Three people! It's the first round, it's ridiculous. We are not on TV, there is nobody watching, nobody is watching the stream. You're ridiculous!"

Flentie protested his innocence, telling Boyer 'we are seeing it differently' and 'we are not going to just bend the rules'. But the American continued ranting as he stormed off court, picking up his racket and giving it one last smash on the ground for good measure.

On paper, Boyer was expected to get the better of Bolt at the ATP Challenger Tour event in San Diego. The California native is steadily working his way up the rankings and last year became the first American to win three clay-court Challenger tournaments in a single season.

Now, the world No. 113 has his sights set even higher. "The next goal is Top 100, rankings wise," he revealed in November. "Being the best I can be is always the goal.

"Doing the right things, process wise. Making the right decisions in terms of what we are working on, how we are getting better to make sure we can keep on the right path and the results will show at some point."