But it could not dampen the veteran's spirits as he opened his Latics account seven games into a loan spell from Hull.
A delighted Sheridan said: "We were worthy winners. We could have scored three or four more goals and I am delighted to beat a team who are very hard to play against.
"The early goal made a difference because it forced Northampton to come out, which opened up a bit more space for us to play our football.
"And I am obviously pleased for Dean Windass because 200 goals is a great achievement and he keeps showing why I brought him here at the age of 39."