Speaking to BBC Radio Solent, Bournemouth boss Eddie Howe said: "It was really tough to break them down.
"I thought they defended very well and made it difficult for us."
Opposite number Ian Sampson, who has now seen his side keep three clean sheets in a row, told BBC Radio Northampton: "We defended well as a team, especially in the second half."
He added: "To get a win is important. In the context of the season, we've got momentum going so we'll take it into the next game."
That next game is at home to Chesterfield on Saturday when a win could take Town into the top-half of the League Two table.