The Addicks top scorer, Elise Hughes, tapped in for her sixth of the season ten minutes before the break to ultimately settle the contest.
They were well on top for the majority of the first half, with the two Lois’s – Heuchan and Roche – forming an at times unplayable double-act.
Roche created the game’s first chance of note with her quick feet, finding Elisha Sulola in a pocket of space, who could only slice wide.
Megan Wynne and Sulola both narrowly missed out on the end of searching deliveries from Jorja Fox and Hughes, respectively.
When Mia Ross smacked one inches over from 20 yards, it only added to the inevitability of a Charlton goal.
And, minutes later, Hughes broke the deadlock. Rhian Cleverly’s pass was intercepted by Heuchan, who drove to the byline before cutting across to give Hughes the easiest of tap ins and leave Tatiana Saunders in the Lewes goal stranded.
Ini Umotong poked just wide when she might have done better as Lewes rallied before drawing a superb low save out of Eartha Cumings just before the break.
The Rooks were more competitive after the interval - Georgia Timms providing a welcome spark - and they were unlucky not to draw level when Freda Ayisi saw a brilliant long-range effort cannon off the crossbar.
Izzy Dalton’s well-struck free-kick was comfortably held by Cumings, and Saunders bravely thwarted Wynne at the other end as both teams showed ambition in the final third, but the hosts held on to build on an unbeaten run which began in mid-November.
The result leaves Lewes seventh, and they host ninth-placed Sunderland at the Dripping Pan next Sunday.
Lewes midfielder Izzy Dalton said: “That first half was sloppy from us and we weren’t good enough. We did try and put things right, but we didn’t get enough shots off and didn’t put our chances away, so it’s probably a fair result,”
“It came down to the simple fact that we weren’t on the front foot. We weren’t aggressive enough, we weren’t communicating and it was all the simple things that we are usually so good at.
“We didn’t play our football and we need to be better with the football. It was a cheap goal to giveaway and defensively, playing out, we needed to be better – that’s where we fell short.
“The only good thing to come from it was that it was us being sloppy, rather than them breaking us down. This week in training it’ll be working on doing the basic things right because when we do that we are a good footballing team.”
Charlton Athletic captain, Lauren Bruton said: “The main thing today was the three points and we really desperately needed the win, especially with Lewes being a point behind us with a game in hand,”
“We looked comfortable for most parts of the game. Lewes did come out in the second half but we dealt with it well and deserved the points, so it was a good day.
“We are doing really well defensively and have picked up lots of clean sheets, but it’s putting the ball in the back of the net where, at the moment, it’s maybe just the one a game. That’s something we are looking to improve. But today, we’ll take it.
“The pressing was relentless and the tactics from us were spot on, which led to the goal. When you’ve got someone in your team like Wynney (Megan Wynne), it’s her game to a tee and Lewes tried to play out whenever they could, so the high press was perfect for us.”
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Lewes (4-4-1-1): Tatiana Saunders; Rebecca McKenna, Nicola Cousins, Rhian Cleverly (c), Zoe Cross; Paula Howells, Ellie Noble, Izzy Dalton, Lucy Ashworth-Clifford; Freda Ayisi; Ini Umotong. Substitutes: Georgia Timms for Umotong 46, Ellie Hack for Noble 46, Amelia Hazard for Cleverly 82 Substitutes not used: Laura Hartley (gk), Shanell Salgado (gk), Heidi Logan, Izzy Collins, Josie Longhurst
Referee: Jade Wardle