David Ripley admitted his disappointment after Northants failed to convert a strong batting display at Scarborough.
The Steelbacks made 310 for seven from their 50 overs in the Royal London One-Day Cup clash, but they were eventually beaten by two wickets by Yorkshire Vikings.
County old boy David Willey steered the home side to victory, hitting a six to secure the win and take his unbeaten total to 26.
He had earlier taken two for 55 as the Steelbacks racked up the runs, with Ben Duckett blasting a List A best of 121 from 113 balls.
And Ripley said: “I thought 310 looked a good score for us and I was disappointed we did not win because I felt our performance deserved better.
“We stuck in there after being put in to bat on a damp pitch and in heavy overcast conditions and it was a very fine partnership between Duckett and (Alex) Wakely.
“Then Yorkshire must have had a word with the big man up there for the sun came out for their innings.
“We didn’t have the rub of the green but Adam Lyth made a dent in our hopes with a very fine innings.”