But it was a chastening experience for Fulham, who faded badly after a bright start and must already be fearing another long, hard season.
Boateng beat strongly in Hull's engine room, but is an early injury concern after being carried off with an ankle injury, leaving his team to face five minutes of added time with only ten men.
But Hull looked comfortable, as they had done for most of the game, following Giovanni's match-changing equaliser midway through the first half.
Taking a pass from Sam Ricketts, the Brazilian ran across the face of the defence before spotting a gap and sending a left-foot shot beyond Mark Schwarzer's reach.
Schwarzer had denied Hull a dream start with a great save from a Giovanni header in only the second minute, but Fulham soon took control as Simon Davies and Jimmy Bullard dictated the midfield battle, threatening to make it a miserable start for the league's new boys.
Fulham took the lead after eight minutes when Ki-Hyeon Seol glanced Bullard's right-wing cross passed Boaz Myhill.
Roy Hodgson's team should have been out of sight in the next few minutes but Davies, Bullard and Zoltan Gera missed gilt-edged chances.
With Nick Barmby and Ian Ashbee providing strong support for Boateng, Hull gradually found their feet and well on top after half-time.
But Giovanni missed a sitter when he put Barmby's measured pass wide.
Bobby Zamora set up Fulham's best chance of the half with a pass into the six-yard box which no-one could reach.
Phil Brown's three substitutions between the hour and the 73rd minute paid off dramatically.
Peter Halmosi provided fresh legs and undoubted class down the left and Craig Fagan set-up for the winner for Folan.
Fagan muscled Paul Konchesky off the ball and crossed to the far post where Folan shot home.