To make matters worse, the hosts were robbed of a penalty when both referee Anthony Taylor and his linesman ignored a blatant shirt pull by Ben Gibson that stopped Salomon Rondon reaching a dangerous Galloway cross.
From there it went from bad to worse with Boro boss Karanka about the only man happy with the way it turned out.
“I was really pleased with the reaction to losing at Fulham in the EFL Cup and it shows how we have great spirit among the players,” he said.
“We have five points on the table and the club has worked really hard in the summer. The intensity was the same as we showed last season.”
WEST BROM (4-2-3-1): Foster 6; Dawson 5, McAuley 6, EVANS 7, Galloway 6; Fletcher 5, Yacob 6; Phillips 6, Field 6 (Gardner 76), McClean 5 (Leko 64 6, Berahino 71); Rondon 4.
MIDDLESBROUGH: Guzan 5; Nsue 5, Ayala 6, Gibson 6, Barragan 5; Stuani 5 (Fischer 90), Clayton 5, FORSHAW 6, Downing 5; Ramirez 5 (Nugent 84), Negredo 4.