Lambert has admitted that his side deserved to lose and lamented avoidable errors and a lack of concentration.
"We got what we deserved. We lost poor goals at bad times of the game," the Scot told reporters. "The poor goal from a cross was poor. The second goal, Guzan says he should have saved it, then we switched off at a free kick.
"We spoke about not switching off against Everton. They finished in the top five last year. We had to be better and we take our medicine.
"When we lost the first goal, we came into the game, but we were well beaten."
Villa have conceded 11 unanswered goals in the process of losing their last four top-flight games.