The scoreline from August’s meeting at Tannadice was repeated in the Clydesdale Bank Premier League clash at Dens Park.
Keith Watson headed the visitors in front and Irish striker Jon Daly doubled their lead from the penalty spot before Flood’s deflected strike brought the third goal.
Flood said he would “definitely” claim the goal, which was attributed in some quarters to defender Kyle Benedictus.
“I don’t score many,” he said. “It was a shank but it was a goal and that’s all that matters.
“We’ve actually played better than that and not got the results, I didn’t think we passed the ball well today but we were a threat up front. The boys played really well and every time we got the ball to them we looked like scoring.”
Elsewhere, Celtic rounded off a momentous week with a convincing 3-1 Clydesdale Bank Premier League victory over Kilmarnock at Rugby Park.
The Hoops’ 2-1 home win over Spartak Moscow on Wednesday night sealed their place in the last 16 of the Champions League and they continued their good work in Ayrshire, starting when skipper Scott Brown fired them into the lead in the 27th minute.
Second-half goals from midfielder Joe Ledley and substitute Georgios Samaras were just reward for the Parkhead side’s dominance, before Cillian Sheridan grabbed a late consolation.
The win keeps Celtic three points clear of second-placed Inverness, who were 3-0 winners at home to Hibernian.