Sheffield Wednesday chalked up their third defeat in a week when they lost at League One neighbours Chesterfield.
Megson axed top scorer Gary Madine, opting for Ryan Lowe to partner Chris O’Grady in attack. Left-back Reda Johnson returned after a two-match suspension, while John Bostock was named a substitute after missing the midweek defeat to Stevenage with illness.
Lowe had the first clear chance of the game, heading over the crossbar after a cross from Reda Johnson, who was then thwarted by goalkeeper Tommy Lee as the Owls made an impressive start.
Chris Lines picked out Lewis Buxton from a far-post corner, but the ball was behind the owls defender and he could not find the power to beat Lee.
Megson was forced to make an early substition when Jermaine Johnson limped off to be replaced by Bostock on left side of midfield.
Stephen Bywater was called into action when he palmed away Liam Ridehalgh’s 25-yard shot as the hosts enjoyed their first spell of pressure as the half-hour mark approached.
The loss of Johnson had certainly impeded the Owls as an attacking threat, but Lowe should have put Wednesday in front when he turned his marker in the box only to drill his shot wide.
Bywater had to be alert to keep out Drew Talbot’s effort as the Spireites grew in confidence from the visitors’ inability to convert their superiority into goals.
Danny Batth had to throw his body in front of Dean Morgan’s goal bound shot,mwith Megson throwing on strikers Clinton Morrison and Gary Madine in a 4-3-3 formation.
Bostock conceded a penalty with 13 minutes remaining after a clumsy challenge and Morgan fired home from the spot.
Rob Jones had a header cleared off the Chesterfield line as Wednesday looked for an immediate response, but they failed to find an equaliser