Jack Redshaw's cool finish from a long clearance had put the Shrimps a goal to the good at the interval.
But after the break it was all the Bees as Luke Gambin levelled from Dani Lopez's pass before the Spaniard took over, firing in a hat-trick that included a penalty after goalkeeper Barry Roche was given his marching orders for hauling down Gambin.
"A disappointing day for us and a bit embarrassing to be fair," Bentley said. "That's not one of our performances.
"We we're just all over the park and it was a bad day at the office. We've been doing well of late and we've tried to keep everything nice and positive all week.
"We've got to stand up and be counted and take that on the chin. I've said to them 'all of you have got look at yourselves in the mirror and ask yourself questions' and that's staff included.
"They pinned us in our half, we're 1-0 up they have had a couple of chances but I always thought we were going to score another one.
"When we lost against Plymouth tactically it was wrong, here everything was correct."