Dragons endured a difficult night on home soil as the ruthless Irish side pulled away in the second half to complete a comprehensive win.
Jones refused to make excuses for Dragons after the game and instead vowed the squad would go back to working harder than ever on the training field and make amends next time out.
“We are all very disappointed by that performance,” said Jones. “We gave them some easy ins to the game and it wasn’t the ideal start.
“If you give a team like Leinster a sniff they can be ruthless and they have come here to put four tries on us and they have succeeding in that goal.
“We need to go back to the drawing board on Monday and look at that performance because it wasn’t good enough.
“I wasn’t expecting the performance we put on the field. We gave them too much time, made too many basic errors and you can’t do that against a quality team.
“We have a good group of players here,” he added. “They are a young group, all 23 were Welsh qualified today, and as far as I’m concerned we have got to go back to work on Monday and do our job.”
Dragons face two difficult trips in the European Challenge Cup over the next two weeks and Jones acknowledged the team would need to step up to the challenge ahead of them.
“We’ve got a couple of tough weeks with Northampton and Clermont away from home in Europe, we know how tough that is going to be,” he said.
“But we have got to prepare right and take that into the next few weeks before we go into the Welsh derby games.
“We weren’t good enough on the day. We’re all disappointed, I felt we could have done a lot better than we did and we all feel that and have to get better.”