Having arrived in India among the favourites, the 2019 champions are set to depart on Sunday among the also-rans, having scrambled to a seventh-placed finish.
With six defeats from nine games, this goes down as the country’s worst ever performance at the event, leaving Mott under pressure after 18 months in the job.
Some read Key’s decision to jet out to Kolkata for the end of the tournament as a bad sign for the Australian, but he and captain Jos Buttler instead received the backing of their boss.
Rather than line either up as a blood sacrifice, Key focused on his own prioritisation of England’s Test fortunes, which have sparked to life under Brendon McCullum’s guidance.
“I look at what I’ve not done rather than blaming everyone else. I hold myself accountable for a lot,” he said.
“Since I’ve started this job, it’s very hard for me to be critical of Jos Buttler and Matthew Mott when I’m the one who, every single time a decision has been made around whether or not we focus on 50-over cricket, Test cricket or T20, I’ve always chosen Test cricket.
“When there was a choice in Pakistan over who got the best players, I’ve always said, ‘sorry, Test cricket gets that focus at the moment’. The same thing in South Africa. I’ve always chosen Test cricket. It’s not easy for coaches and captains when you haven’t got the ability to plan and have your best team.
“That’s not their fault. So I feel like it’s harsh if I turn around and blame the captain and coach. Really, I hold myself at the top of that list for what’s gone wrong on this trip.”
Key’s backing for Mott did come with a gentle reminder that the mandate was not open-ended, with next summer’s T20 World Cup an obvious barometer for improvement.
“As far as I’m concerned he gets my full backing. He’s the person to get the first opportunity to put that right,” said Key.
“But it’s certainly not a case of saying ‘carry on, let’s keep doing everything the same and get the same result’. You’re now the person charged with sorting this out – along with myself, along with Jos, along with everyone else who has any kind of decision-making authority in English cricket. It’s for everyone to be accountable for that.
“It’s pretty simple as a coach, your job is to make sure that every single player is improving and getting better and that’s what we haven’t done. He will accept that.
“I feel this actually should be the making of those two (Mott and Buttler) as a partnership. If it isn’t, it isn’t and you move on but we have to make sure some good comes out of what has been a very poor World Cup.”
Key suggested another decision he had got wrong was in not hiring somebody with greater knowledge of Indian conditions to their backroom team. When England won the T20 World Cup in Australia last year they not only had Mott’s expertise, but two other locals in David Saker and Michael Hussey as coaching consultants.
England have been guilty of picking the wrong teams, failing to judge a par score on particular pitches and made some poor calls at the toss. Most obviously, they opted to field first against South Africa in energy-sapping heat and humidity in Mumbai and were promptly run ragged.
“I set up a coaching team that had no local experience really,” he reflected.
“When you get to somewhere like Mumbai – and it all seems so simple now – you’re worried about dew and all of this other stuff. But someone who knows these conditions really well would say ‘it’s hotter than the sun out there; make sure you have a bat’.
“It was only in the last couple of games, have we actually understood the way that we went about things. We should have known this but we didn’t going into the competition.”
There will be more analysis in the coming days and weeks as England try to come to terms with going from all-conquering champions and 50-over trailblazers to a seventh-placed side feeding on the crumbs of Champions Trophy qualification.
But Ben Stokes may have said it best on the eve of England’s penultimate game against the Netherlands when he summed things by saying ‘the problem is we’ve been crap’.
Key, ultimately, could not put it better himself.
“I would agree,” he concluded.