A 1-1 draw with lowly Wigan Athletic denied West Brom the chance to climb back above Leeds United at the top of the Championship.
West Brom recorded the biggest win of Slaven Bilic's tenure to go back to the top of the Championship with a 5-1 thrashing of Swansea City.
Bristol City's 2-0 win at Fulham put the Robins right in the promotion picture, while leaders Leeds United beat Huddersfield Town.
Millwall looked to be heading for defeat, but Aiden O'Brien got a late equaliser in a 2-2 draw with Nottingham Forest.
West Brom beat Preston North End 1-0 at Deepdale on Monday to record a fifth successive Championship win and climb back into top spot.
Brentford scored seven times in a rampant win over Luton on a day when Leeds went top of the Championship with West Brom not playing.
Fulham are two points off the automatic promotion places in the Championship after Aleksandar Mitrovic's brace sank Swansea City.
A comfortable home win over Bristol City moved West Brom back into top spot, while Garry Monk avoided defeat against his former side.
Leeds United claimed a late win over Reading to move top of the Championship as Michael O'Neill suffered his first loss as Stoke City boss.
Garry Monk had some choice words about his former Birmingham City assistant Pep Clotet, leading to a retort from the Blues.