Brentford 0 Nottingham Forest 2
Brentford fell to their first home defeat of the season as Nottingham Forest claimed a 2-0 victory on Saturday afternoon.
The Bees, who had won seven and drawn one of their opening eight Premier League fixtures at Gtech Community Stadium, started the game well but goals either side of half-time from Ola Aina and Anthony Elanga secured the three points for the visitors.
Thomas Frank made three changes to the starting XI from the Carabao Cup quarter-final defeat at Newcastle United as Christian Nørgaard returned alongside Mikkel Damsgaard and Bryan Mbeumo and the Bees reverted to a back four.
They replaced Ethan Pinnock - who picked up a hamstring injury at St. James' Park - Yehor Yarmoliuk and Fábio Carvalho, with the latter duo being named amongst the substitutes.
Brentford had the first opening of the game with just over three minutes played. Mbeumo played the ball around the corner for Yoane Wissa, who then pulled it back into the middle of the box for the arriving Damsgaard but the Danish midfielder saw his left-footed shot parried by Matz Sels.
Mbeumo created the next opportunity under five minutes later but his dangerous cross from the right wing, coming after a corner was only half-cleared, was headed wide by Kristoffer Ajer.
Mark Flekken was brought into action for the first time on 18 minutes, as he caught Chris Wood's tame effort from just inside the D following good work from Morgan Gibbs-White.
Wissa went close at the other end shortly afterwards, bringing down Morato's miskicked clearance which flew straight up in the air, before his acrobatic effort looped onto the roof of the net from eight yards.
Moments later, Mbeumo flashed the ball across the face of goal, just out of the reach of Wissa, as the Bees continued to dominate.
A superb save from Flekken prevented Forest from taking the lead at the other end. Wood met Elliot Anderson's cross from the byline but the Bees keeper somehow turned his header around the post with a strong left hand.
The visitors did open the scoring on 38 minutes, though. Neco Williams reached the byline and pulled the ball back across the box, with Wood missing it before Aina arrived to pass into the bottom corner.
Forest doubled their advantage early in the second half. Elanga pounced on a rare loose touch from Keane Lewis-Potter before driving into the box and curling into the bottom corner of Flekken's goal.
Brentford continued to push numbers forward with the visitors being a constant threat on the counter-attack as Flekken pulled off a smart stop to deny Elanga a quickfire brace.
Sels preserved Forest's two-goal cushion with a stunning reaction save on 62 minutes. Damsgaard's back-post cross was nodded back into the middle by Mbeumo for Ajer, who struck his volley well but the Belgian keeper somehow palmed it over the bar.
Mads Roerslev, who had only just been introduced from the bench, then came up with an important intervention of his own as, after a touch from Collins took an Aina cross away from Wood, he got his leg in the way of Hudson-Odoi's effort on the rebound.
The Bees continued to push for a way back into the game but Forest held firm, repelling numerous balls into the box, to register a clean sheet.
Roerslev was forced from the field in the final minute of extra-time after an elbow inadvertently cut the defender's head.
Brentford: Flekken; Ajer, (Roerslev 67 (Konak 90+5)), Collins, Mee, Lewis-Potter; Janelt (Maghoma 67), Nørgaard, Damsgaard; Schade (Carvalho 81), Mbeumo, Wissa
Subs not used: Valdimarsson, Yarmoliuk, Meghoma, Ji-Soo, Yogane
Nottingham Forest: Sels; Murillo, Milenković, Morato; Aina, Gibbs-White (Silva 75), Anderson (Domínguez 64), Williams (Toffolo 90+3); Elanga (Yates 64), Hudson-Odoi; Wood (Awoniyi 90+2)
Subs not used: Miguel, Ward-Prowse, Moreno, Boly
Attendance: 17,115