Millwall have recorded a sixth successive away win in the Championship thanks to a 2-0 victory at Barnsley on Saturday.
The hosts fell behind on 24 minutes after giving the ball away in midfield as Lee Gregory went on to slide home the opener following a low cross from Jed Wallace.
Lions midfielder George Saville came close to adding a second just before the break but blazed over the bar from a dangerous position.
Ben Marshall managed to double Millwall's lead just after the hour with a ferocious 25-yard effort which left Barnsley goalkeeper Nick Townsend helpless.
George Moncur and Oliver McBurnie went close for the Tykes, while Gary Gardner missed a gilt-edged late chance to grab a consolation goal.
In the end Barnsley could not find a reply and fell to their ninth home defeat of the campaign.
Nuno Morais's side are now without a win on home turf in their last 11 attempts, a run stretching back to early November, and they remain fourth from bottom in the table.
For the Lions, the result was a sixth win in their last seven games which edges them up to ninth place.
BARNSLEY (4-3-3): Townsend; Yiadom, Jackson, Lindsay (Isgrove 81'), Pinillos; Potts (Bradshaw 66'), Gardner, Mallan (Moncur 46'); Thiam, Moore, McBurnie
MILLWALL (4-4-2): Archer; Meredith, Hutchinson, Williams, Romeo; Marshall (Onyedinma 79'), Cooper, Saville, Wallace; Morison, Gregory (Shackell 75')
