But a try from Richard Birkett in the closing minutes condemned Warriors to defeat and left Hill demanding his players learn to close out close games.
"It is very disappointing and it is cruel to lose right at the end," said Hill. "It just shows you have got to keep going.
"Our defence had been very good for the whole game and then one lapse in concentration and Wasps capitalise. They spotted the mistake and that was it.
"It was criminal what we did at the end," he added. "One forward, who will remain nameless at this stage, unfortunately didn't roll away. That is a very dull penalty to give away when you are 12-9 up in the closing minutes.
"You have got to close the game down and Wasps were not going anywhere. That was criminal and that penalty has cost us.
"But we should also defend from the lineout, but a lapse at the back has seen three players miss Simpson. One error led to another, but you just can't afford to concede a penalty with a couple of minutes to go.
"Wasps were not going to go anywhere, our defence had been good all night and we have let it go.
"I'm not happy about it. I will look at the tape, but I have an idea who it was and I will be having a word with him later on. If it's a dull penalty then he will get blasted because that has cost us."