An early goal from Gabriel Agbonlahor was enough to condemn the Reds to their second loss of the season, as the visitors stretched their unbeaten run at Anfield to four matches.
"We were slow in our pressing and passing early on and gave away a bad goal, but then we upped it," BBC Sport quotes him as saying.
"It was a frustrating day but I think it was a combination of Aston Villa defending well and us failing to find that wee bit of quality. We had enough of the ball but could not find the penetration in the final third."
Liverpool are currently eighth in the Premier League table.