A late score from Julien Dupuy took the points for Tigers and Ruddock admitted the missed kicks at goal from his team and not being clinical had been costly.
"It was a great contest, fantastic match and everything great about the Guinness Premiership," he said.
"The intensity of the game and the quality of the collision was first rate. I have congratulated the team for a fantastic effort but we are disappointed to lose.
"It's one of those we feel we should have won having outscored them two tries to one. The kicks to touch, kicks at goal, they are the things that have cost us the game, that is what let us down.
"We know the standards we need to hit to win games of this magnitude and we just failed with that on this occasion.
"But we have to remember that Leicester are one of the top clubs. We outscored them in terms of tries we have just failed to be clinical in some areas and that let us down."
After the match much debate surrounded a penalty kick by Toby Flood that was given just before the break with many supporters questioning whether the England international had been successful.
But Ruddock refused to blame that moment for home defeat and said: "It was a big call. It was difficult from where I was sitting, I didn't originally thing it was over but it is in the record books now.
"There are always crucial points in any game. Wasps will look at last week and point to key moments.
"Sometimes they go for you and other times they don't. Hopefully it will even out."
Warriors lost Chris Latham and Chris Horsman to injury and Ruddock had differing reports on the Worcester duo.
"Latham has gone to hospital as a pre-caution. The medical team has looked at him and decided that is the best option," he said.
"He walked off as he didn't want to be carried off. Despite going to hospital we don't anticipate anything sinister. Whether he is available for next week is another thing.
"Chris Horsman suffered a dead leg, he tried to run it off and couldn't. It is a soft tissue issue so shouldn't be too bad but he is distraught because he wants to be playing."