It was the first of seven Ashes tons during the streak, which has prompted enormous praise from greats Steve Waugh and Ricky Ponting, plus captain Tim Paine and coach Justin Langer.
Initially, England had named an unchanged squad for The Oval, but it came with the caveat that if all-rounder Ben Stokes was deemed unfit to bowl because of a shoulder injury, then he would play as a specialist batsman, with one of the top order batsman to make way.
Australia beat England in Old Trafford in the fourth Test to take an unassailable 2-1 lead in the series to retain the Ashes.
"We've got the best fast bowler in the world (Pat Cummins) and the best Test batsman in the world", he told Sky Sports.
While Smith is the leading scorer in the series with 671 runs in three tests, team mate David Warner has struggled, scoring only 79 runs in eight innings with three ducks.
But Langer is adamant Smith was mimicking Chris Rogers, who last played for Australia in 2015 and, like Leach, wears glasses when he bats. "He's had an opportunity to come in and play Test cricket, get a feel for it, and it's not quite gone how he would have liked".
Root stressed that he is fully focussed on trying to secure a series-levelling win against Australia before embarking on what he hopes will be successful winter tours of New Zealand and South Africa.More news: Red Sox Fire Dave Dombrowski
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"I'd say after spending that much time in the middle and the emotions of the last game - sometimes with batters it's more a mental rest than anything else", Langer said.
"We have not lost anything yet".
"I've got a feeling he might hit a few balls tomorrow".
"He'll be fine. I've said throughout the whole series if Davey has one good innings he'll help us win the Ashes".
Australia retained the Ashes in Manchester a couple of days ago and the visitors celebrated the moment to the hilt later. I don't know why people are getting so offended.
"We are very hungry, we have already spoken a lot about it", he told reporters on Wednesday.
"He sent me that pic, I woke up to that pic this morning, saying he'd done it in honour of me", Rogers said on The Grade Cricketer podcast.