United defender Jones, who returned to the side after being dropped against Huddersfield Town last time out, admits that the mood is low in the dressing room following a second defeat in three top-flight outings.
"We didn't show up today, we started slow," he told Sky Sports News. "They pressed us, the crowd were on their feet. We got control midway through the first half and should have scored but we weren't at the races, we weren't good enough, simple as.
"For whatever reason we weren't good enough. Ultimately we have conceded a sloppy goal. The lads are devastated in the dressing room."
United face Huddersfield in the fifth round of the FA Cup next weekend, before then travelling to Sevilla for the first leg of their Champions League last-16 tie.