After
Mowbray made five changes to the side which twice came back to earn a 3-3 draw against Cardiff however the Baggies extended their unbeaten streak to five games with goals from Roman Bednar, Robert Koren and Kevin Phillips putting Albion in the hat for the next round.
"It was a professional display," Mowbray claimed.
"We came out of the blocks pretty quickly and scored two goals.
"We expected a tough game and we got a tough game.
"
"They've got a lot of good attacking players."
The battle of the country's two highest scoring teams saw on loan Czech striker Roman Bednar continue his impressive scoring form netting 11 goals in the last 13 appearance for the Baggies - not to mention his winning spot-kick against Charlton in the last round. Bednar made way for fellow hot-shot Kevin Phillips at half-time who also found the net via a 58th minute penalty.
"When you've got good options you've got to try to pick the right ones," Mowbray added.
"Thankfully we did that today.
"Roman's been under the weather with flu symptoms.
"He's been recovering during the week and wanted to give it a go today.
"He got his customary goal - as did Kevin.
"The plan was always to give Roman and Kevin 45 minutes each.
"They both scored so they're both reasonably happy."