Expected to run riot again at their Gtech fortress after some customary unsuccessful away days, Brentford were not short of chances in the opening period of Saturday's game, but Frank's men were made to pay for profligacy.
Ola Aina's crisp finish put Nuno Espirito Santo's men a goal to the good not long before half time, and the hero of the Aston Villa win - Anthony Elanga - was on target early in the second to put the Tricky Trees within 30 minutes of a place on the Premier League podium.
It was backs against the wall for the visitors as the clock wound down, but Thomas Frank's men just could not pick the Garibaldi lock as they lost a Premier League game to high-flying Forest for the very first time.
For at least a couple of hours, Forest will be sitting pretty in third place in the Premier League table above Arsenal - who face Crystal Palace in the evening kickoff - while Brentford have slipped to 12th place after losing their Gtech golden touch.
SPORTS MOLE'S VERDICT
The story of Brentford's season so far had been breathtaking home performances coupled with miserable away days, and Frank's men were aiming to score three or more goals for the sixth Premier League game running on their own patch.
The Bees ran into an unexpected Forest formation, as Santo switched to a 3-4-3 setup with Elliot Anderson and Morgan Gibbs-White pairing up in the middle, potentially leaving them vulnerable to rapid counter-attacks from their hosts.
However, the visitors executed their manager's tactical plan to a tee, absorbing copious amounts of Brentford pressure and taking their chances when they came at the other end of the field, something home specialists Bryan Mbeumo and Yoane Wissa surprisingly failed to do.
Forest will now spend Christmas Day four points clear of Manchester City - surely a scenario beyond any of their fans' wildest dreams - and Santo's surprise package continue to strengthen their case for Champions League football either week.
For Brentford, Frank's men must ensure that their first home setback of the season does not signal the start of a slippery slope in West London, as their pitiful away form would epitomise that of a side fighting relegation as opposed to pushing for a top-half place.
BRENTFORD VS. NOTTINGHAM FOREST HIGHLIGHTS
38th min: Brentford 0-1 Nottingham Forest (Ola Aina)
An early contender for the Premier League Team of the Year? Maybe a bit premature, but Ola Aina has been terrific for Forest this season and makes his mark in West London with seven minutes to go before half time.
The visitors surge forward through Callum Hudson-Odoi and Neco Williams, who gets to the byline and sends a low ball into the mixer, which somehow evades Chris Wood and the desperate lunges of two Brentford defenders.
However, Aina is on the scene and finds the bottom corner with an incredibly composed first-time finish.
38th min: Brentford 0-2 Nottingham Forest (Anthony Elanga)
The unbeaten home record is under serious threat now! Nikola Milenkovic punts a long free kick forward which Keane Lewis-Potter cuts out, but his touch is heavy and Elanga nicks in.
Ben Mee fatally drifted out of position too, giving Elanga all the space and time in the world to charge inside and find the bottom corner in front of the away fans.
MAN OF THE MATCH - OLA AINA
Not discounting the applaudable defensive efforts of Murillo and Matz Sels, Forest wing-back Aina was instrumental at both ends of the field in the capital, taking his finish with the panache of a seasoned number nine.
The 28-year-old also put in six clearances, three interceptions and two tackles as Forest somehow kept Brentford at bay, while also succeeding with two of his three dribble attempts for Santo's Champions League contenders.
BRENTFORD VS. NOTTINGHAM FOREST MATCH STATS
Possession: Brentford 64%-36% Nottingham Forest
Shots: Brentford 7-10 Nottingham Forest
Shots on target: Brentford 3-6 Nottingham Forest
Corners: Brentford 9-5 Nottingham Forest
Fouls: Brentford 9-14 Nottingham Forest
BEST STATS
WHAT NEXT?
Once the Christmas festivities are over, Brentford hit the road to battle Brighton & Hove Albion at the Amex on December 27, before kicking off 2025 at home to London rivals Arsenal.
Forest have Boxing Day preparations to attend to, though, as Santo's men host Tottenham Hotspur on December 26, just three days before a trip to Everton.
Written by
Ben Knapton