Fireworks in the stadium before kick-off marked the imminent birthday of the Leicester City chairman, Vichai Srivaddhanaprabha, but they were nothing compared to the rocket launched in the 25th minute by Wilfred Ndidi. The Nigerian midfielder reached a landmark of his own by blasting a ferocious long-range shot into the net to claim his first Premier League goal and give his team a lead that they never looked like losing. Jamie Vardy confirmed the victory in the second half by scoring with a fine volley.

Further vindication was perhaps the gift desired most by Srivaddhanaprabha, who turns 60 on Tuesday, and a fifth win from five matches since Craig Shakespeare assumed managerial duties amounts to a strong endorsement of the club owner’s decision to sack Claudio Ranieri in February.

This was a day when anyone doubting Leicester was made to look foolish. Twenty-four minutes had elapsed when the Stoke City fans struck up a chant of “Champions of England – you’re having a laugh” whereupon Ndidi wiped the smile off their faces in the most satisfying way. After receiving a pass from Danny Simpson, the 20-year-old took one touch to set himself up for a shot that seemed ill-advised and then thrashed the ball into the top corner from 25 yards. He hit it with such power that by the time the Stoke goalkeeper Lee Grant had finished diving, Ndidi was already cupping an ear to savour the cheers of the Leicester supporters and the stunned silence of the visitors. Shut-ups have seldom been more spectacular.

In truth the Stoke contingent had been jeering the hosts merely in the name of terrace repartee rather than to denounce Leicester’s performance, as the champions had been the superior side in a bright first 25 minutes. Demarai Gray, who would have been on the bench if Marc Albrighton had not reported ill in the morning, was causing regular trouble down the left wing with his speed and trickery, even after Ryan Shawcross upended him with a late tackle in the 17th minute. The free-kick following that foul almost led to a goal, Christian Fuchs’ delivery provoking a goalmouth scramble and forcing Erik Pieters to head the ball away in a panic before Glen Johnson intervened to stop Vardy from converting from close range.

Mark Hughes, the Stoke manager, admitted afterwards that his team “were a yard short all day” but it was only after Ndidi’s rocket that Leicester really took flight. Shinji Okazaki went close with an overhead kick following a corner, his effort whizzing over the bar. Then Riyad Mahrez tried to join in the fun with a devilish low shot from 20 yards. This time Grant’s dive was not in vain and the keeper managed to tip the ball around the post.

If the interval came at an opportune time for Stoke, they did not seem to make wise use of it as less than two minutes after the resumption they fell further behind. Their problem began with another incursion by Gray, this time down the right, and it was aggravated when the winger laid the ball back to Simpson, who swept in a cross that caught Johnson dozing. There were no flies on Vardy, however, and the striker took advantage of the full-back’s negligence to wallop the ball into the net with a terrific volley from 12 yards.

That was the England striker’s sixth goals in his last eight matches in all competitions, a tally that reflects his rejuvenation since Shakespeare replaced Ranieri as manager.

Further evidence of Leicester’s transformed fortunes came in the 70th minute, when Marko Arnautovic had a goal disallowed after being wrongly flagged for offside.

Leicester are still only six points above the relegation zone but no one is talking any more about them becoming the first reigning champions since 1938 to drop out of the top flight. Instead Leicester helped Shakespeare create a small piece of history of another sort, as this victory made him the first British manager in the Premier League era to win his first four league matches in charge. The only other men to have done so are Pep Guardiola, José Mourinho, Carlo Ancelotti and Guus Hiddink. “I’m at a very, very early stage in my management career but to be mentioned in the same breath as them makes me very proud,” said Shakespeare. “You sometimes have to pinch yourself.”

Hughes, a veteran in the management game, is suitably impressed with his counterpart. “He’s doing exceptionally well. He’s got a good team, a good group, and he’s getting what he wants out of them at the moment. Being a No1 is completely different to being a No2 but he’s making a good fist of it.”