The New South Welshman was part of breakaway groups three times during the 147.7km stage and notched an emotional victory. It was the 21-year-old’s first win in four years, coming after he almost quit cycling following three difficult years at the AIS.

“It’s my first win in a long time. I’ve had a lot of misfortune the last couple of years, a lot of broken bones,” Donnelly said as he fought back tears.

After racing for more than four hours in temperatures which soared above 40 degrees, Donnelly had to dig deep to hold off Victoria’s Calvin Watson and New Zealand’s Josh Atkins in a sprint around the Tom Flood Sports Centre track to the finish line. 

The trio crossed the line in 4:04.36, more than two minutes ahead of the next two riders.

“I started cramping big time at about 10kms to go and I didn’t think I’d be able to have a sprint at the finish, so coming into the velodrome I just knew it would be best to lead out…I’m just glad it came off,” Donnelly said.

With extreme temperatures forecast, race organisers brought the race’s start time forward two hours but the stage was still held in sweltering conditions.

That didn’t stop the 108-strong peloton from setting a fast early pace, though.

Defending champion Nathan Haas (Jayco Australian Team) led an 11-man breakaway after 20kms, which included Donnelly and Watson (Jayco VIS).

Haas took the opening King of the Mountain stage at Mount Macedon, but suffered a mechanical failure during the descent and was caught by the peloton.

The rest of the breakaway was reeled-in, only for another breakaway of five riders to open a 2:30 gap shortly after.

After missing that attack, Donnelly (Huon Salmon-Genesys Wealth Advisers) and Brad Linfield (Degani Bakery Café Academy) worked together to bridge the gap.

The move paid dividends, as the group of seven opened a six-minute break on the peloton.

“We were just sitting about 1:30 behind the front guys and there was a bit of doubt there for a while but we managed to bridge across,” Donnelly said.

“When me and Brad were trying to bridge the gap that took a lot out of me, but I was able to recover once I caught them and I had a lot of confidence at the end.”

Donnelly, Watson and Atkins (Grays Online NZ National Team) then broke away before One Tree Hill and kept their advantage to the Tom Flood Sports Centre.

“Just before the mountain three of us got away and we drilled it all the way to the finish line,” Donnelly said.

Donnelly takes a 14-second overall lead from Watson into today’s 146.6km second stage from Mitchelton Winery to Healesville.

The final stage finishes at Arthur’s Seat on Sunday.

He also leads the sprinter’s standings with 22 points, ahead of Watson and Atkins on eight points - plus the best under-23 rider classification in front of the same two riders.

Defending champion Haas leads the King of the Mountains classification with 24 points, in front of Chris Jory with 16 points.