A solitary first-half goal from Abel Hernandez was enough to earn Hull a 1-0 victory and leave 10-man Nottingham Forest frustrated at the City Ground.
There were suspicions of offside when the forward bagged his fifth goal of the campaign in the 41st minute, after Sam Clucas had provided the flick-on from a Shaun Maloney corner.
Dorus de Vries had previously saved a Hernandez penalty, after Matt Mills had clipped the heels of Maloney in the box - and the Forest defender's afternoon got worse when he was sent off with three minutes left, following a foul on Chuba Akpom.
Allan McGregor had to make an outstanding save to deny Forest the lead when Nelson Oliveira attempted to bend a precise shot inside the post from the edge of the box, with the keeper getting across brilliantly to palm the ball around the upright.
De Vries was little more than a bystander when Mohamed Diame let fly with a 20-yard effort that was struck with incredible power but rattled back off the bar after taking a slight deflection.
The breathless, end-to-end theme continued as Mendes sent O'Grady angling in on goal, with the big striker forcing another sprawling save from McGregor as an unmarked Mendes screamed for a return pass in the centre.
Referee Nigel Miller incurred the wrath of the home fans when he awarded a penalty to the visitors after Maloney had gone down following slight contact from Mills as the pair chased into the box.
But De Vries produced heroics to keep the score at 0-0, kicking away Hernandez's spot-kick as the striker sent a shot low to the keeper's left.Hernandez did manage to beat the keeper, from virtually on the line, just before half-time as Maloney's corner was flicked on.
The questions over whether he was offside saw referee Miller and his colleagues trudge off the pitch to a chorus of boos from the home fans at half-time.
Oliveira resumed his battle with McGregor at the start of the second half, with the keeper athletically plunging to his left to push away another low shot from the forward.
Michael Dawson was denied a goal against the club where he began his career by a low save from De Vries at his near post as Hull threatened again from a corner.
Substitute Jamie Ward tested McGregor with a stinging shot, while Mendes flashed a shot across goal and wide.
A late flashpoint between Clucas and Eric Lichaj earned both players a booking, after the Hull winger had engaged in a wrestling match with the defender.
But there was a red card in the 87th minute as Mills clattered into substitute Akpom.
Mills had previously been booked, but it appeared that Miller showed him a straight red card.
Forest still almost levelled, with Curtis Davies heading clear a goalbound drive from substitute Tyler Walker.
Source : PA