It meant Huddersfield went into the international break above more illustrious competition after eight wins from their first 11 matches.
Wagner, who continues to be linked with Derby, admitted: “I am very surprised as the only teams who could have expected this start is Newcastle, Norwich and Aston Villa.
“But I am not surprised by how my players are working together and how fit they are. In football, it is all about the little details and getting these details right to win games. For any manager in the Championship, three points at Ipswich is huge.”
Asked if he would be interested in the Derby job, with Nigel Pearson suspended, Wagner would only say: “I don’t talk about myself – it is all about my team and my players.”
The first half was largely forgettable with few clear-cut chances. Town’s Elias Kachunga hit the inside of a post with Nahki Wells’s rebound pushed away by Bartosz Bialkowski.
Ipswich had fleeting moments, but were unable to prevent their run without a goal going beyond 400 minutes.
Schindler’s goal secured a first win at Portman Road in 20 years as Wagner brought back Mark Hudson and Chris Löwe after suspension, with Jonathan Hogg also returning for his 100th Town appearance.
He played with Dean Whitehead in front of the back four to combat Ipswich’s direct style aimed at winning ‘second balls’, with Aaron Mooy pushing forward into the ‘No 10’ slot.
Wagner made a change at the interval, introducing van La Parra in place of Whitehead to inject more pace and Schindler later departed with a cut eye.
Ipswich Town: Bialkowski, Emmanuel, Chambers, Berra, Knudsen, Douglas, Skuse, Ward (Sears 57), Bru (Bishop 57), Lawrence (Varney 86), Best. Unused substitutes: Gerken, Digby, Grant, Kenlock.
Huddersfield Town: Ward, Smith, Hudson, Schindler (Hefele 71), Lowe, Whitehead (van La Parra 46), Hogg, Scannell (Cranie 87), Mooy, Kachunga, Wells. Unused substitutes: Holmes-Dennis, Coleman, Payne, Palmer.
Referee: C Kavanagh (Lancashire).
Man of the match: Aaron Mooy.