But Saints showed a clinical edge in the final quarter to pull away and take the points in front of a sell-out Sixways crowd.
"We didn't nail down our golden periods - times when we had real field position and pressure," said Ruddock.
"In fairness to Northampton, when they had their periods they nailed down scores just about every time. That was the big difference between the two teams, I guess that is why they are near the top of the league and we are down the bottom end.
"I thought our effort was really good, although we possibly dropped our heads a little bit towards the end. Maybe that was a little bit of fatigue kicking in, we had given it our best shot and had to do a lot of defending in the second half.
"They intercepted a number of lineout balls and cut down our possession flow which was good in the first half. They went up a gear when they sniffed a chance to cut away from us.
"The game was all on a knife edge for a long time and I thought we were in a good position to go on and win the game," he added.
"Unfortunately Willie (Walker) missed the chance to make it 9-9 and then we missed a drop goal option with Matthew (Jones). Little margins which could have just pushed us into putting them under pressure.
"It didn't quite happen and then they go down the other end and score. We put up a kick that could have bounced up into Miles Benjamin's hands and he could have been away for a score.
"Instead it bounces to Ben Foden, who is probably the most dangerous player on the field. He breaks through and finds Chris Ashton outside him. The two guys we didn't want the ball to get to - that was the crucial moment in the game.
"But up until then I thought we were extremely competitive and really took the game to Northampton."
Warriors failed to score a try to extend a long run without crossing the whitewash in the Guinness Premiership on home soil.
But Ruddock insisted he would be more concerned if his team were not creating the chances to breach the opposition try line.
"We had a five metre lineout, which is a bit of a trademark for us, and they managed to catch the inside arm of one of our guys and the ball just spilled away.
"Little things like that went against us. You have the Miles Benjamin interception in the first half, if he had just evaded Ashton we are in for a try. Also Rico Gear going down the wing and looking like he might score.
"We had lots of chances, but we didn't nail them down. I would be more worried if we weren't creating these opportunities. We have just got to keep trying to take them and work under pressure more and more often to get better."