New Southend manager Sol Campbell watched on from the stands as the nine-man Shrimpers crashed to an eventful 7-1 defeat to Doncaster at Roots Hall.
Southend had Ethan Hamilton sent off after just six minutes for a challenge on Jon Taylor but still took the lead five minutes later with Isaac Hutchinson firing home a fantastic free-kick.
Doncaster levelled with a header from Kwame Thomas in the 23rd minute before Ben Sheaf netted with a deflected volley three minutes later.
Thomas made it 3-1 with another simple finish in the 52nd minute before Southend's Stephen McLaughlin was shown a red card for a foul on Taylor.
Ben Whiteman made it 4-1 with an assured 20 yard shot in the 70th minute before Sadlier netted from six yards after Taylor's effort had bounced back off the post.
Substitute Alfie May lobbed the ball over Nathan Bishop to make it 6-1 in the 89th minute before Nathan Ralph deflected Taylor's right wing cross into his own net.