Cool Khawaja sures up his Ashes spot

Usman Khawaja has all but locked in his spot in the Australian top order with a sterling JLT Sheffield Shield century but is refusing to even think about England until his domestic commitments are over.

The Queensland skipper scored a match-defining 122 as his side wrapped up a comprehensive win against Victoria on Saturday with a full day to spare.

He was the only man who could tame a tricky Gabba pitch in a performance that augurs well for next month's opening Magellan Ashes Test at the same venue, where he is expected to bat at first drop.

But the 30-year-old, who has been in and out of the Australian side in recent months, was reluctant to look any further ahead than the next two rounds of the Shield.

"You can't get too far ahead of yourself in cricket, it bites you on the backside," Khawaja told AAP.

"We've still got two more games for Queensland – that's a lot of cricket. It could be another eight days, possibly another four innings for me.

"I just have to keep my head down and keep trying to score runs for Queensland and win games and then whenever the Ashes rolls around, I'll concentrate on that then."

Khawaja was left stranded on 99 not out at stumps on day two on Friday.

It brought back painful memories of last year's Boxing Day Test against Pakistan, when he was on 95 not out overnight but was dismissed the next day without adding to his score.

This time around, Khawaja tucked off his hip for a single from the very first ball he faced on Saturday afternoon to bring up his 21st first-class ton.

"I had a great night, 11 hours sleep. In all honesty I wasn't really that nervous," he said.

"But the win's actually the one that makes me feel a bit better."

Meanwhile, Khawaja was full of praise for towering young paceman Brendan Doggett, who grabbed five wickets on his Sheffield Shield debut – four of them coming at crucial moments during Victoria's first innings as they were bowled out for just 148.

Originally from Rockhampton, the 23-year-old is highly regarded by state coaches and by his captain, who said he had all the makings of a future star.

"It feels like he's got an old head on young shoulders," Khawaja said.

"I know he's just starting off at the moment but he's got all the skills, he's got the stamina to keep bowling.

"He bowls fast. He doesn't really drop off. They're pretty good attributes to have at such a young age.

"I've faced him a little bit this year but the nets are never the same as the game. I was a bit unsure as to what to expect. I'm really impressed by him."