But free-flowing Irish were inspired by a hat-trick from wing Marland Yarde as they ran in six scores and Hill conceded the defence had not been good enough from Warriors.
However, with Defence Coach Phil Larder back at Sixways next week he expects to see an immediate response.
"I'm disappointed and the main area was the defence," admitted Hill.
"I was pleased with our scrum and our lineout, pleased with our penalty count that was less than London Irish and some of our attacking play was encouraging.
"To score three tries away from home is a good feat. So many areas were very good yet we just leaked tries too easily.
"We have had two weeks in the Amlin Challenge Cup against Rovigo and Gernika when we haven't had to do any defending. We also have deliberately concentrated on our attack and not done any defence work for a few weeks.
"But next week Phil Larder comes back in after three weeks away and this is a fitting game for him to analyse and get us back on the straight and narrow.
"I am looking at that display thinking the set piece is good, the discipline is better and we scored three tries way from home. If we can bolt on our defence, which is normally very strong, then next week should be different.
"We had a few different players in the pack and we probably lacked a little bit of ball carrying," he added.
"When we have some of our front liners back in the pack it will be different, you could see the energy when we made changes in the second half. When we bring the likes of Aleki Lutui and one or two others back in then we will get more go-forward."