The all-rounder went on a rampage on day one of the fifth Test at The Oval, in the most dominant display by an Australian No.3 in two years.
Watson brought up his hundred with a guided drive through the covers off James Anderson and raised his arms in sheer relief.
His ton came from just 114 balls with 16 fours and one six.
It's the first time an Australian No.3 has posted a three figure score since Shaun Marsh against Sri Lanka in 2011.
Elevated to first drop following Usman Khawaja's omission, Watson is one of nine options Australia have used at the poisoned chalice first drop position in the past three years.
James Faulkner's presence in the team was perhaps a reminder to Watson that he's not the only all-rounder in the Test picture.
But Watson responded in emphatic style.
The 32-year-old has been under constant scrutiny due to his poor return rate of two hundreds from 45 Tests, mostly spent batting in the top order.
Apart from some nervous early moments with the ball hitting his pads, Watson powered his way to 80 from 77 by lunch, enjoying a field day facing England debutants Simon Kerrigan and Chris Woakes.
However, he was finally confronted with some adversity when on 84.
Batting partner Chris Rogers departed to end their 107-run partnership, and then three overs later Watson was floored by a vicious bouncer from a fired-up Stuart Broad.
Broad sent a bumper that struck Watson under his helmet and behind his left ear - the batsman turning his head and taking his eyes off the ball at the last moment.
Watson was in all sorts of pain, throwing himself to the ground, before physio Alex Kountouris and doctor Peter Brukner rushed to his assistance.
However, Watson dusted himself off and went on to bring up his first century since October, 2010 against India in Mohali.
Since then he's been out between 50 and 99 no less than 10 times.
Although this is a dead-rubber Test against a weakened England attack, Watson was at his brutal best.
He blasted his way to 50 from just 61 balls, with 42 of those runs scored in boundaries.
Watson has had a disappointing series so far, shunted from opening to No.6 and now moved back to the top order to be Australia's third No.3 of the series.
He's also had to deal with negative headlines emanating from his fallout with former coach Mickey Arthur.
Watson, who also scored 68 at Chester-le-Street, overcame a groin injury and took full advantage of England's decision to treat the dead-rubber Test as a chance to blood new talent.
Watson treated debut spinner Kerrigan (0-28 from two) and rookie medium pacer Woakes (0-30 from five) with absolute disdain.
He smashed six boundaries off each, accounting for 48 of his runs.
In Kerrigan's second over, Watson carted him for 18 runs, including four fours.
Watson also went after Kerrigan in last week's tour game between the Australians and the England Lions and it was a tough Test initiation for the left-arm orthodox spinner - who was picked over misbehaving veteran Monty Panesar.
Given Australia's penchant for top order collapses this tour, Watson's knock was even more commendable given he came to the crease with Australia 1-11, and Rogers and Michael Clarke fell while he was approaching the milestone.