The Blues ended an eight-game wait for a win with a 2-1 triumph over the Foxes at Goodison Park thanks to new signing Theo Walcott's first goals for the club, both coming in the first half.
But while match-winner Walcott stole the headlines, right-back Coleman was equally sublime on his first-team return.
Despite having not featured since last March - 319 days ago - having suffered a double leg break while playing for the Republic of Ireland, Coleman was as fit as any player on the pitch, as shown in a few lung-busting drives.
Coleman's contributions in attack and defence helped to ensure that Everton claimed a much-needed three points despite Jamie Vardy's second-half penalty piling on the pressure and ensuring a tense finish.
"Marvellous" Coleman set the precedent
Speaking at his post-match press conference, Everton boss Allardyce reflected: "Good gracious me, can you imagine if they had got an equaliser?
"Well I'm really pleased obviously to take the three points. I think that as a performance and a win, [it was] not always comfortable in the performance but most of the time we were.
"I think there's a new partnership flourishing that's come together for the very, very first time, which is Seamus and Theo. I think everybody could see what an impact those two had today playing together.
"Theo could have scored a hat-trick today. Oumar Niasse could've scored a hat-trick, that's how many chances and good chances we created.
"Oumar doesn't miss many chances not only on the pitch but in training. That was quite unusual for him to miss so many.
"There was a bit of nerves when the penalty went in, which was a silly thing to give away at that stage because Leicester weren't offering much and that gave them a bit of impetus.
"We got a bit of lucky off the post and bar, which I'm glad to say but I thought we deserved that bit of luck.
"Certainly the performance was good and the partnership down that right-hand side was excellent today.
"For him [Coleman] to finish 90 minutes and in the 92nd minute run 80 yards with the ball was outstanding and is an example to every player at this football club.
"When you've been out for 10 months and you can perform with his sort of energy and quality that he did today, it's just marvellous to see.
Allardyce full of praise for right-sided pairing
Goalscorer Walcott and the energetic Coleman were the stand-out performers down Everton's right side and continually combined to great effect.
On how the duo dove-tailed so well despite it being the first time that they had played together, Allardyce added: "Quality, nothing more to say about it. Quality and understanding.
"Obviously Seamus has played against Theo quite a lot, knows him and sees him.
"[There was] That instant combination today of the support for each other both ways, if you look at Theo out of possession and the covering he gave to Seamus as well, which was all a part of the game for us today.
"We put the right game together defensively and attacking-wise. If [there's] anything I can be slightly upset about, [it was] that penalty and not getting the clean sheet we were looking for today. But the win was the most important thing."