In a captivating and controversial contest in which Willy Boly was sent off, Anthony Elanga and Chris Wood's efforts would seemingly rescue a point for the hosts, but the irrepressible Dominic Solanke scored a brilliant hat-trick - capped off with an injury-time header - to leave the Reds crestfallen.
An intriguing and offensive-minded first Forest selection from Santo saw both Divock Origi and Wood chosen to spearhead the attack, with Elanga and Morgan Gibbs-White also involved from the first whistle.
Bournemouth boss Andoni Iraola did not shy away from a couple of changes either, swapping out Justin Kluivert and the ill Milos Kerkez for Philip Billing and Dango Ouattara, but the Cherries were on the back foot early doors.
Wood and Elanga both forced Neto into saves within the space of two minutes, but having weathered that early storm, Bournemouth began asking questions and came within inches of an opener in the 14th minute, when the red-hot Solanke fired just wide of the near post.
However, officiating controversy once again reared its ugly head at the City Ground, as with 24 minutes gone, Boly - who had been booked inside the first five minutes - was made to take the walk of shame for a challenge on Adam Smith.
Boly's tackle was by and large a clean one, but Rob Jones saw fit to brandish the red card as the ex-Wolverhampton Wanderers man caught Smith on the follow-through, and Santo responded by sacrificing Origi for Moussa Niakhate.
Bournemouth were also forced into an early change, as Lewis Cook limped off to be replaced by Alex Scott, and the Cherries survived a heart-in-mouth moment in the 37th minute, as Smith escaped giving away a penalty despite blocking a Harry Toffolo cross with his outstretched arm.
The VAR room apparently could not definitively conclude whether Smith's arm was in or outside the box, and even though Forest held out until the break, the City Ground erupted in boos towards the under-fire Jones.
The home crowd swapped boos for cheers just two minutes into the second half, though, as Wood robbed Scott of the ball in a dangerous area and slipped through Elanga, whose first-time strike rolled into the bottom corner.
However, the City Ground's elation died down only four minutes later, as a sublime Marcos Senesi cross from the left was on the money for Solanke, whose looping header sailed over Matt Turner and into the side of the net for his ninth top-flight goal of the season.
Only seven minutes passed before the Bournemouth marksman moved onto double figures for the Premier League campaign, as Billing's header with his back to goal fell kindly for Solanke, who raced in behind an unawares Forest backline to slide home into the bottom corner.
The Cherries fans began taunting the ejected Boly, but they were made to eat their words in the 74th minute as 10-man Forest drew themselves level through Wood, whose header from a Gibbs-White corner somehow evaded a few Bournemouth heads before finding its way in.
With their tails up, Santo's side then saw a Gibbs-White curler cleared off the line by Ouattara in the 81st minute, three moments before Bournemouth went down the other end and struck the post through substitute David Brooks.
The depleted hosts appeared set to take home a slice of the spoils, but with five minutes gone in injury time, Solanke demonstrated his aerial mastery once more to send the away end into delirium, meeting a Smith delivery and beating Turner with a stunning header from 12 yards.
The Forest goalkeeper could only push Solanke's treble-clinching header further into the roof of the net, as Bournemouth rose into 11th place on account of their fifth win from six games, while Santo's Forest are now just two points clear of the drop zone in 17th.
Both teams will take to the field for Boxing Day fixtures, as Forest welcome Newcastle United to the City Ground for a lunchtime kickoff, before Bournemouth host Fulham on the South Coast.