O’Brien was unseeded for the tournament but prevailed 2-6 6-3 6-1 in the final to make the honour board for the first time.

The 25-year-old coach is on the comeback trail from wrist surgery and was surprised to be the last man standing from a field of 64.

“I came here thinking I would do decent, but it was only my second tournament back in three years,” O’Brien said.

“You always expect to do well, but you never expect to win.

“Mark’s a great player as well, so it was always going to be tough.” 

O’Brien said he didn’t panic after making a slow start.

“He (Shanahan) blew me off the court in the first set, so I tried to refocus and reset for the whole match,” O’Brien said.

“I started to get on top a bit and just kept on going from there.

“My serve helped out a lot. I hit a fair few crucial serves on big points, and my forehand started going in a bit more than it was in the first set.”

In the women’s singles, the ACT’S Tallulah Farrow defeated Mildura rival Sheree Moore 6-2 6-1 to take the title. Farrow, 14, was the top seed and justified her ranking with a powerful display.

But while the scoreline gave the impression of a one-sided match, Farrow said Moore made her work hard for the victory.

“Last time I played Sheree it was close,” Farrow said.

“I think I lost 11-9 in December, so I knew it was going to be hard, no matter what the score.

“Even the matches coming through were tough. Everyone played really well, but the match against Sheree was the best.

“Overall, though, I was really happy with how I played.”

Farrow said Griffith’s clay courts suited her talents.

“We train a lot on clay, especially over this period of time,” she said. 

“We’ve been hitting on clay a lot now that it’s coming up to winter, so it’s probably my best surface.”