The result saw Quins move to the top of the Aviva Premiership with Leicester in third. Tigers play second-placed Saracens at Welford Road on Saturday (kick-off 8pm).
And Flood says: "It is really tight up there with teams chipping away at each other. It is always going to be a tough feat to finish first and second and we know how important a home semi-final is and the statistics that go around that and how many teams go through on that so it's imperative for us to make sure we work as hard as possible to get there.
"We set our sights on winning these two and putting a bit of distance between us but now we have to go home and beat Saracens to maintain where we want to be."
Flood's points haul included a 70-metre interception try after he picked off Nick Easter's pass early in the game.
He says: "I just realised that Nick Easter was throwing that and I just gambled and, luckily for me, I got it and just about had enough pace to get there.
"It wasn't pretty for the next 15 minutes, I felt pretty sick after three weeks sat around doing nothing so it was nice to get over anyway."
Tickets for Tigers' Aviva Premiership game against Saracens at Welford Road are available now from the Tigers ticket office in person, on 0844 856 1880 or online by clicking here