Sean Dyche watched his squad given a stern test on his return to former club Chesterfield.
The Clarets led 2-0 after just 22 minutes of an entertaining contest at the Proact Stadium, with Lukas Jutkiewicz and George Boyd reprising their goalscoring exploits from the opening warm-up game against Etoile Carouge.
But Dean Saunders’ side hit back with goals midway through both halves by Jake Orrell and a stunning overhead kick from sub Armand Gnanduillet.
And the Spireites snatched a late winner when Byron Harrison bundled home an 88th minute winner.
Dyche was given a rapturous ovation ahead of kick off at the club where he spent seven years as a player.
On the pitch, goalkeeper Tom Heaton made his first start of pre-season, after recovering from a dislocated finger.
However, striking options were again limited, with Jelle Vossen, Sam Vokes and Marvin Sordell all still sidelined with minor knocks.
That left Jutkiewicz to lead the line, with Boyd playing just behind in the hole. And the new-look strike-force wasted little time showing their credentials.
Clarets targetman Jutkiewicz was desperately unlucky not to fire the Clarets ahead in the 11th minute.
Chesterfield-born Matt Lowton picked him out with an inch perfect diagonal ball from right back and Jutkiewicz, drifting beyond the last defender, controlled brilliantly on his chest before his fierce volley was brilliantly tipped onto the underside of the bar by Tommy Lee in the Spireites goal.
Two minutes later though, Jutkiewicz got his reward for a bright opening. This time Boyd started the move with a penetrating run, before sliding in Fredrik Ulvestad in the right channel.
The Norwegian fed the ball wide to Lowton, whose low first time cross from the right was slotted home effortlessly at the near post by the inrushing striker.
Within minutes, Burnley almost doubled their lead when Boyd’s snapshot following a goalmouth scramble was cleared off the line.
But the Scot didn’t have long to wait to add his second goal of pre-season, sent clear midway through the half by Ulvestad and coolly rounding Lee to slot the ball home.
Little had been seen of Chesterfield going forward, but they reduced the arrears in the 26th minute when Orrell converted Tendayi Darikwa’s cut-back from the by-line.
But Burnley remained firmly in the ascendancy and came close to extending their lead again on the stroke of half time.
First Lee denied Lowton with a point-blank save and from the resulting corner, desperate defending again led to a goal-line clearance.
Dyche resisted the opportunity to make changes at half time, and the Clarets again emerged on top.
Jutkiewicz just over-ran the ball when Scott Arfield found him with a raking ball over the last defender, and just after the hour Arfield jinked his way into the box and fired straight at Lee from a tight angle.
But out of nowhere, in the 67th minute, the Spireites were level with a sensational overhead kick from substitute Gnanduillet.
The Ivorian had his back to goal on the edge of the box, but met an angled ball perfectly with a stunning scissor kick that beat Heaton, came back off the inside of a post and nestled in the opposite corner of goal.
Lowton came close to restoring the lead as the game ticked into the final quarter, seeing his deflected cross clawed off the line by Lee at his near post.
But a late Burnley winner would perhaps have been harsh on the hosts, who won it themselves with two minutes remaining as Harrison converted from close range following good work from Gnanduillet.
BURNLEY: Heaton; Lowton, Duff, Keane, Mee; Kightly (Taylor 72), Jones, Ulvestad, Arfield, Boyd, Jutkiewicz (Jackson 85).
Subs: Gilks, Lafferty, O'Neill, Ward, Hewitt, Anderson, Dummigan.
CHESTERFIELD: (starting): Lee, Darikwa, Jones, Hird, Evatt, Banks, Morsy, O'Shea, Gardner, Ebanks-Blake, Orrell.
Subs: Raglan, Kearns, Humphreys, Onovwigun, Ariyibi, Dieseruvwe, Harrison
Ref: C Pawson