In the moment, the collection of another landmark might not mean a great deal to Brook. Despite his efforts, his team were beaten as the spirited Sri Lankans pulled off the second-highest run-chase in history in one of the most astonishing ODIs ever played.
For a man who has previously spoken about prioritising match-winning contributions over individual achievements, Brook the captain was left dejected that his innings ultimately counted for nothing. He is the first man to make a double ton in an ODI and end up on the losing side.
Still, it further underlined his status as the premier run-getter across all kinds of international cricket. Perhaps only Australia's Travis Head can challenge Brook for the crown.
Ranked by the International Cricket Council as the best Test batter in the world, Brook averages 53.08 in the longer format of the game. No England player with a minimum of 20 innings since 1968 has a better average than Brook – he stands above Joe Root, Alastair Cook, Geoffrey Boycott, Graham Gooch and everyone else to have batted for England in the past seven decades.
In T20 internationals, Brook averages 36.21 at a strike-rate of 164.92. No batter to have played at least 20 innings for a major nation averages more at a better strike-rate.
Brook is learning to play List A cricket in one-day internationals. Sri Lanka was his 61st List A match, 45 of which have been ODIs. After a slow start to his international 50-over career, Brook averages just under 50 in his past 29 matches and almost 57 in 2026.
The responsibility of captaincy suits him. In ODIs, Brook averages 31 runs more as captain compared to when not. In T20s, his average jumps 19 runs when wearing the metaphorical armband.
Brook's workload is an issue, the Yorkshireman having played in every England fixture since being rested for a T20 series in Ireland last September and, fitness permitting, he will be the only man to play in every game this winter – that's five tours to four countries across three continents. He left home last week and will not again see his own bed until mid-January.
He says his time to rest is during the Indian Premier League, the riches of which he has turned down in order to focus his energy on England. Brook probably does not get enough credit for making such a decision.
There is the question of how good Brook could become. Ben Stokes revealed that, at the end of the Ashes, he took Brook to one side to say he should be averaging 60 or more in Test cricket.
Speaking to the BBC in August, Brook admitted to not being the "finished article".
"I have the ability to hit it everywhere, I just have to figure it out quicker in games," he said.
In terms of improvement, Brook has already shown a willingness to do the hard yards to become a better cricketer.
As a youngster, he struggled with his fitness, but has worked hard to become one of the best athletes in the England team. He has spoken at length about being better able to run twos – he is one of the best runners between the wickets in the world. Brook has also turned himself into one of England's most reliable catchers.
As for the batting, well-qualified judges don't hold back in their praise. Last month, Stokes said Brook may have more talent than Kevin Pietersen. In 2024, James Anderson said Brook could surpass Root as England's highest Test run-scorer. Just last week, Chris Woakes labelled Brook as "next level".
The missing achievement is a starring role in winning a major series or tournament.
Brook's magnificent century should have been enough for England to win the fifth Test against India at The Oval last year, only for him to throw away his wicket with victory in sight. He has not made a century in 10 Ashes Tests against Australia and was only a bit-part player as part of the England team that won the T20 World Cup in 2022.
Maybe his moment is approaching. Next summer is a home Ashes, followed by the 50-over World Cup in southern Africa. Brook will be 28 and at the peak of his powers. There is the chance to play a major part in regaining the urn and to become one of the few British athletes to lift a World Cup in any sport.
To do that, he will have to iron out the flaws that have arisen in England's one-day cricket across the first two matches of the tri-series in Pakistan.
In the opening match, against Pakistan, dropped catches and poor strokes left them well beaten in a contest they could have won.
Against Sri Lanka, England somehow lost from what seemed an impregnable position, their bowling and fielding falling apart amid a growing realisation they were in danger of failing to defend a target of 430.
There was some mitigation. Dew made the ball incredibly slippery, while their attack was weakened by the absence of the rested Jofra Archer and benched Adil Rashid.
Nevertheless, the bowling was awful, particularly Sam Curran, who conceded 103 from nine overs to return the worst figures by an England bowler in an ODI. It was an error by Brook to continue to show faith in the left-armer, while not using the full allocation of 10 overs from either Josh Tongue or Gus Atkinson.
It is one of the first major missteps of Brook's captaincy career and the sort of performance that shows England still have some way to go to be seen as serious World Cup contenders.
Now, England will have to win their next two matches to reach the tri-series final, to be played on 31 October, exactly 12 months on from Brook's horror show in Wellington.
England need the sort of turnaround their captain has managed over the past year