Huddersfield manager David Wagner urged the Terriers to build on their 4-1 FA Cup extra-time win against Birmingham as they fight for Premier League survival.
Championship Birmingham went toe-to-toe with their Premier League opposition but it was the visitors who progressed to the fifth round following a replay at St Andrew’s.
The reward for Wagner’s side is a last-16 home tie against Manchester United.
Che Adams put Birmingham ahead in the 53rd minute and the opening goal saw the contest spark into life.
Tom Ince began Huddersfield’s revival with a powerful shot which ended with Marc Roberts turning the ball into his own net.
A three minute purple patch in the first period of extra time enabled Huddersfield to seal the game, as Steve Mounie and Rajiv van la Parra knocked all the fight out of Birmingham before Ince completed the scoring.
Wagner said: “We were not clinical enough in the opening 45 minutes. We could easily have doubled the score.
“I was very pleased with the performance, the effort and attitude. It was a fully deserved win against a difficult Championship side.
“We are delighted to be in the next round and to play Manchester United at home. First and foremost we are happy to have won as it is a win we required to build up the momentum for the Premier League.”
Huddersfield have lost their last five Premier League matches and Wagner hopes their cup run can help them end that streak against Bournemouth.
“The longer the game went on, we were able to create opportunities and score goals,” he said.
“Fitness wise we are at top level and it lifts the confidence playing in the Premier League. This is why our next home game against Bournemouth is so vital and why we have to make it an extraordinary
Birmingham boss Steve Cotterill admitted his side had been blown away in extra time.
“We kept it tight in the opening 45 minutes but going into extra time was always going to be a tall order,” he said.
“This was our 11th game in 46 days and this match was too much as the lads were dead on their feet at the end.
“After taking the lead we needed another goal in 90 minutes as we didn’t need extra time in our present circumstances against a Premier League side.
“There was nothing we could do about fatigue. I could not be more proud of the lads as they didn’t give in.
“But we couldn’t cope with extra time and credit Huddersfield for taking their chances in this period.”