He brilliantly turned away a Robert Earnshaw goal bound drive in the fifth minute of added on time.
Gilks thanked Blackpool boss Ian Holloway for giving him a chance to resurrect his career which went on the downturn at Norwich- and what a way to thank the manager.
Blackpool had the determination to turn the game on its head after being dominated by Forest for long periods of the first half. It was Blackpool's third win over Billy Davies' side and the Seasiders have now gone a 'perfect' ten of victories.
Both sides found it difficult to cope with the swirling wind and bumpy pitch. However on 13 minutes Forest's Chris Cohen revealed some beautiful control on the edge of the penalty area to turn and score with a magnificent dipping shot which completely beat Gilks into the top corner.
Blackpool issued an immediate riposte and a great ball from Charlie Adam found DJ Campbell, who twice in quick succession had blocked shots in the Forest penalty area.
In the 25th minute Blackpool equalised courtesy of a great run from their full-back Seamus Coleman. The Everton loanee took on three Forest players and as everyone thought he was about to shoot he instead played in defender Ian Evatt.
Evatt squared the ball and Keith Southern's half-hit shot still had the power to beat Wes Morgan's attempted goal-line clearance.
The goal breathed life into Blackpool, who began to play the more flowing football but they had to ride out their luck just before the break when Coleman produced a brilliant goal-line stop from Paul Anderson's shot.
With Campbell starting to make himself more dangerous upfront Forest suddenly found themselves under early second-half pressure.
The striker's neat pass put through Charlie Adam, but the midfielder shot wide and then in the 57th minute Campbell's speed outwitted the Forest defence.
He played a one-two with Brett Ormerod and as Campbell was about to pull the trigger he was floored inside the area by James Perch. Adam converted the penalty for his 18th goal of the season.
Forest boss Davies made clear his intentions of trying to take at least a draw back to the City Ground, using three attacking substitutes, but his defence was again in trouble and lucky not to concede another penalty when Blackpool's Gary Taylor-Fletcher was taken from behind with a heavy tackle.