Two Semesa Rokoduguni tries and the boot of George Ford saw the visitors build a 21-0 lead.
And even when Jonah Holmes crossed for his first-ever Premiership try, Matt Garvey ensured Bath had the last laugh with his first league score for his new side.
Bath’s victory was their biggest ever at Adams Park and Young is demanding a much improved outing next weekend against London Irish.
“I can’t offer any excuses, I thought Bath were good but we made them look a lot better than they actually were,” he said. “They didn’t really have to fight too hard for it and that is a disappointing factor.
“It was an unacceptable performance and that is what I said to the players. Next week is a real show of character, a real show of belief and a real show of quality because we lacked quality in everything we did here.”
Saracens stayed top with a 16-9 win over Exeter Chiefs, despite the absence of centre Joel Tomkins, out for three months with a knee injury.
Also on Saturday, James O’Connor scored his first points in London Irish colours but could not prevent a 20-11 reverse at Leicester Tigers.
But tries from Nick Easter, Danny Care and Luke Wallace earned Harlequins a 27-19 home win against Gloucester Rugby.
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