Bournemouth boss Eddie Howe admitted his side had an off-day after losing 2-0 at home to Northampton.
Early goals from Luke Guttridge and Ryan Gilligan gave the Cobblers victory as Howe's side missed an opportunity to narrow the gap on league leaders Rochdale, whose game against third-placed Rotherham was postponed.
"We started badly and things just got worse. We were not at the races," said Howe.
"We were missing Warren Cummings at left-back and he is an experienced player for us and you could see we missed him.
"We had to change personnel and change the system a bit with him out, but the change of tactics has nothing to do with our inability to pass the ball.
"The game was very disappointing but we will move forward from here."
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