Playing against South Africa A and batting at No.4, Warner hit 29 fours and one six in a typically robust innings off 226 balls.
Warner shared a 204 run partnership with Glenn Maxwell (100no) for the fifth wicket before being bowled by quick Marchant de Lange on what became the final ball of the day.
Australia A finished the day at 5-399.
Given Australia's batting collapses so far in the Ashes series, Warner must now be a likely starter for Old Trafford.
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Leading into this match, Warner had gone 11 innings without scoring 50.
He was suspended for the final match of the Champions Trophy and the Ashes tour matches against Somerset and Worcestershire after his drunken night out in Birmingham last month, where he punched England rival Joe Root at a nightclub.
Warner was in contention for the first Test at Trent Bridge, but it was decided he hadn't spent enough time in the middle.
He was dispatched to Africa to join the Australia A squad, and after managing just 6 and 11 in their first match against Zimbabwe, there was pressure on for Warner to deliver against South Africa A.
Warner will bat at No.6 if he returns to the Test side, meaning the likes of Steve Smith and Phil Hughes are now under pressure to perform in Australia's three-day match against Sussex in Brighton starting on Friday.
Now Warner has a score under his belt, Australia seem likely to rush him back in the line-up given his explosive ability with the bat could potentially make a big difference to the stuttering middle-order.
Before heading to Africa, Warner said he hoped to become the new Michael Hussey of the Australian side.
After Australia were bowled out for just 128 at Lord's, any big scores from batsmen in the tour match against Sussex will be hard to ignore.