Two second half goals ended Irlam's hopes of a place in the last eight of the Buildbase FA Vase.
After a keenly contested and goalless first half, the game was delicately poised, but a fine goal by Chertsey's Lubomir Guentchev broke the deadlock four minutes into the second half.
Just after the hour, an already hard job got even tougher for Irlam when they lost skipper Charlie Doyle to a straight red card, and wide man Marcus Perry to injury in the space of a few minutes.
The visitors, currently sitting at the top of the Cherry Red Records Combined Counties Football League, took control of the game from then on, and wrapped up victory with a penalty from Jake Baxter five minutes from time.
The opening 45 minutes were very evenly matched, with Irlam starting the stronger before Chertsey gradually began to pose a greater threat as the half wore on.
After a cagey opening, the game burst into life on the 15 minute mark with chances at both ends.
A long clearance forward found Irlam's centre forward Jordan Buckley, whose flick on found Marcus Perry, and forced Chertsey keeper Nick Jupp into a save at his near post.
The ball was then cleared upfield, and a neat first touch from Chertsey's Andy Crossley took him past two Irlam defenders and set up a shot that Irlam keeper Lee White pushed away at full stretch.
The pace of Marcus Perry down the Irlam right flank has been a feature of the team's performances throughout the season, and like many defences in our Premier Division, the Chertsey defence were struggling to cope at times with the Irlam wide man.
Twice in the space of two minutes just on the half hour Perry caused a threat, first of all blasting a shot over and an angle, and then being denied by a great covering tackle after taking a slightly heavy first touch as he advanced into the box.
But Chertsey were beginning to enjoy more possession, and their full back Sam Flegg missed the best chance of the half six minutes before the break.
Flegg timed his run from deep perfectly to get on the end of an Andy Crossley free kick, but fluffed his lines by failing to get a proper connection on the ball from only a couple of yards out.
Irlam finished the half strongly and a 25 yarder from Matty Boland and a solo run and shot from Jordan Buckley saw them end the half on the front foot.
It had been a close fought affair up to that point, and a game that always looked like the first goal would be crucial, and four minutes into the second half Chertsey made the vital breakthrough.
From an Irlam perspective, it was a disappointing goal to lose, as a ball into the box was diverted into the path of Chertsey's Lubomir Guentchev, but there was no doubting the quality of the finish that Guentchev produced, when he curled a delightful shot into the top corner of the net from the edge of the box.
Events then took another turn for the worse for Irlam just after the hour, when Marcus Perry was injured in a challenge for the ball near the corner flag, and when the ball was cleared upfield, skipper Charlie Doyle was shown a straight card for a scything challenge on goalscorer Guentchev.
Perry limped off injured a few minutes later, never having recovered from the earlier tackle, and with a man advantage Chertsey played a well organised pressing game, pushing Irlam back into their own half, and denying them space to create.
With five minutes remaining, Chertsey made the game safe with a second goal from the penalty spot, and award that was made after a neat 1-2 between Lubomir Guentchev and Jake Baxter saw Guentchev tripped as he advanced into the box.
Baxter made no mistake with the spot kick to seal victory for his side.
Irlam manager Michael Dodd was naturally disappointed afterwards.
"I don't think we can say they didn't deserve to win, but equally if we were to play the game again we would fancy ourselves to go and beat them", he said.
"At half time 0-0 was about right, you had two defences on top, and not many clear openings. It was a 50/50 game, it was there for the taking for either team.
"We had a couple of chances in the first half and nearly broke through, and they did the same, with both keepers making a couple of good saves.
"We talked all week about not making errors at the back, we made one when we switched off for a second and were punished by a great shot into the top corner from 25 yards. We're disappointed we didn't clear the ball but you can't argue with the finish.
"Then the two things which were probably top of the list of things we wouldn't want to happen actually happened.
"Marcus Perry came off injured and Charlie Doyle our captain got sent off, and they are two players we would really want to stay on the pitch.
"I don't blame the referee for us getting beaten, but I did think the red card was very harsh on such a big occasion.
"After that, as much as we encouraged the players, all the loose balls seemed to fall to their spare man, and credit goes to our lads for keeping going".