Despite slipping to a narrow defeat, Chorley secured their place in the promotion play-offs following leaders Barrow’s victory over Tamworth, the only other club still in contention for a top-five finish.
Guiseley, avenging two defeats by Chorley this season, also confirmed their participation in the play-offs with a deserved win.
But the final placings will not be decided until next Saturday’s final round of games.
Two smart pieces of finishing by Adam Boyes settled this contest in which Guiseley looked the sharper more fluent side.
But they were made to work hard by the spirited Magpies who just lacked a touch of imagination and extra edge in the final third.
Boss Garry Flitcroft said: “It was a tough game for us, but we knew it would be hard going into the match.
“In the first half, they were the better side and we didn’t get to grips with the full-backs bombing down the wing.
“I just thought Josh Hine and Jack Dorney were playing a little too deep.
“But once we sorted that out, it looked an even game.
“In the second half, we created chances and they scored against the run of play.
“Chris Almond went through on his own, Harry Winter had a chance and Josh just missed.
“We had our chances but knew they would be up for it. The lads gave me everything yet again but unfortunately it wasn’t good enough.”
Danny Hall was close to giving the hosts an early lead following a corner, a goal-line clearance by Paul Jarvis rescuing the visitors.
Boyes bagged his first on 20 minutes stealing a yard on Andy Teague to meet a free-kick with a firm shot past Sam Ashton.
But Chorley levelled five minutes before the break following a neat build-up,.
Teague crossed perfectly from the right for James Dean to rise highest at the far post and expertly head in his 25th goal of a highly productive season.
Guiseley enjoyed a spell of sustained pressure in the second half and regained the lead on 61 minutes.
Danny Bushell curled in an inviting centre which was nodded on by Oli Johnson for Boyes, who finished with real aplomb.
As Chorley strove to hit back, Josh Hine fired a decent chance straight at keeper Steve Drench, who later distinguished himself with a fine acrobatic save from the ever-dangerous Dean.
But it was Guiseley who almost had the final say in added time.
Nicky Bushell was left one-on-one with Ashton but was indecisive enough for the keeper to foil him with a smart one-handed save.
CHORLEY: Ashton, Ross, Cottrell (Burns), Teague, Doyle, Roscoe, Hine (Almond), Winter, Dean, Dorney, Jarvis. Unused subs. Flynn, Lynch, Mather