Goals from Jon Daly, Craig Conway and Johnny Russell made it 12 matches without a victory - and seven without a goal - for the Easter Road men, who now lie just two points above Hamilton in bottom spot.
The Tannadice boss was thrilled with a second SPL home victory to lift his team to sixth in the table but admitted they fell short of their best.
He said: "I won't fault the players for commitment and effort and resilience because once again they've worked extremely hard.
"But we can play a lot better than that. I'm delighted with the result but I was never quite as comfortable as the scoreline suggests.
"But that's a clean sheet and in two SPL games here we've had a 3-0 and a 2-0 win and I can't ask for any more than six points out of six."