Playing for Weston Creek Molonglo in their Cricket ACT Douglas Cup grand final qualifier against Queanbeyan, Blake belted a record-shattering 291 runs and Jono 205.

It helped their side to a total of 9-668 and saw Queanbeyan skipper Michael Spaseski ultimately forfeit the semi-final at Stirling Oval.

He knew chasing that total on the third and final day of the semi-final was an impossible task.

Blake Dean has spent two seasons dabbling with The Southpaw Project - playing left and right-handed - and produced one of the greatest knocks ever seen in ACT cricket in his biggest game during that period.

The hapless Queanbeyan attack had no answers. For the first time in ACT first grade history, every player in the XI bowled in the same innings.

The Dean brothers have been playing cricket together for almost their entire lives, but it doesn't get much sweeter than their 252-run stand.

“[It was one of the best] for sure. I was trying to remember how many big partnerships we've had. That’s the biggest one we’ve had,” Jono Dean said.

“He was right-handed, so it just goes to show that’s how damaging he can be when he is at his best. To be honest he probably hasn’t practice a whole lot right-handed in the last year or so. It was just really good, I was really happy for him.

“Blake was unbelievable. There were periods there where he had to knuckle down and there were periods where he moved the score along. It was just an absolute pleasure to be out there with him.”

Following the Deans’ batting heroics, Creek skipper John Rogers declared at 9-668 - the club's highest score, and the second-highest in competition history. It ended the game without Queanbeyan even strapping on the pads.

It also ended a lean run with the bat for Blake Dean, who’s seven prior knocks had looked like this - 0, 22, 0, 2, 0, 0, 0.

He wrote his name into the history books by posting the highest ever score by a Creek player in any grade and the third-highest by any player in ACT first grade.

Jono Dean was also breaking records for fun - he moved into 13th overall on the ACT first grade leading run-scorers list with 5,888 and became the first person in ACT first grade history to have three individual scores over 200.

Despite Blake’s mammoth effort, he still doesn’t boast the highest score in the family. Jono scored 300* in 2013 to enter the elite 300 club alongside Queanbeyan great Peter Solway, who pummelled 339 in the 1989-90 season.

“I was thinking that he would knock it off pretty comfortably,” Jono Dean said.

“I think I was more worried about the sixes, I think I hit 19 sixes in my 300 and he only had about 16 at that stage so I was happy for him to take it. He couldn’t get it done in the end, must have been too much pressure on him.”

The Deans meet Eastlake in the decider.