The Tigers had a good mix of their EFL stalwarts and new faces in their opening game.
Only three of their 11 new signings started – including their two most expensive transfers, with Greece goalkeeper Konstantinos Tzolakis and Senegal defender Mendy costing more than £20m.
Swedish winger Elliot Stroud was also given a start – with Australia defender Lucas Herrington and ex-Newcastle full-back Matt Targett also coming on for bows.
By contrast, the player who crossed the free-kick for Mendy to nod in was Regan Slater, who played for the club on loan in League One, and then cost just £50,000 to sign from Sheffield United.
The collective effort impressed BBC pundits and former England captains Wayne Rooney and Alan Shearer.
“Hull’s shape was really good,” said ex-United striker Rooney. “They stuck to the job and worked hard which is what they’re going to have to do to try and stay in this league.
“And obviously, it looked like they identified a weakness in United in putting balls into the box and utilised that really well.
“All they can do is try to take as many points at home as they can. It’s a great start.”
Shearer added: “Hull have been absolutely outstanding. They’ve been miles the better team.”
Already the talk of whether Hull could even break Derby’s record low of 11 Premier League points in 2007-08 has died down.
And Jakirovic said this result might also make them more appealing to potential signings before the end of the transfer window.
“Even now, players we wanted, it might make their decision easier. We have to continue like this,” he added.
Commentator White said: “Today might just be one Premier League win from what will obviously be an incredibly challenging 38-game season, but it’s what it represents that means as much as anything.
“Sergej Jakirovic has once again engineered the masterplan to overcome the odds. However, is unquestionably the biggest achievement to date, although the play-off run and the final itself still takes some beating.”
The 32-year-old Ajayi, who netted the opener after Oli McBurnie’s shot had been tipped on to the post, said: “We’ve tried to block out the outside noise and focused on what’s inside the building and what the gaffer is telling us.
“We came out the blocks firing, had a really good start. All in all a really good performance and something to build on for the rest of the season.
“We know what we have in the squad, it was about proving that to ourselves and everyone else.”