Lerner says current results will have no impact on appointing new boss...
The 49-year-old, who has taken charge of the Villans since Martin O'Neill walked away five days before the new campaign, chose to field youngsters Marc Albrighton and Ciaran Clark in the club's first away game this season.
And their lack of experience left Villa helplessly exposed, as the Tyneside outfit capitalised to put six goals past their hapless opponents, with Andy Carroll bagging a hat-trick.
"We started the season well last week so it's disappointing to get well beaten by a decent Newcastle [United] side," MacDonald told ESPN.
"It might have been a bit too much playing a couple of young kids who had done very, very well... maybe I was a bit wrong with my team selection."
The story could have been an entirely different one if striker John Carew had managed to hold his nerve and score from the spot early on.
However, the stand-in claret and blue manager insists his side still had a chance and that they feel hard done to by the score-line.
"The missed penalty changes things to a certain extent," he added.
"We started very, very brightly but it was probably the second and third goals which killed us just before half-time. Momentum is a big thing in football.
"The players felt hard done by at 3-0 but I thought if we got next goal we could get back into the game. But it wasn't to be."
Despite the dreary defeat at St James' Park, Villa owner Randy Lerner has maintained that there will be no change in his approach to appointing a permanent manager at Villa Park.
"Today's [Sunday] result won't change my thinking," Lerner added. "I've said come the end of next week I'd sit down and look at things."