Brentford boss Thomas Frank believes dispatching Premier League Southampton in the Carabao Cup should serve as a benchmark in his side's quest to mount another promotion push.

The Bees, agonisingly beaten by west London rivals Fulham in last season's Championship play-off final, proved their might against top-flight opposition by upsetting a full-strength Saints side at St Mary's.

First-half goals from Christian Norgaard and Josh Dasilva secured a 2-0 south-coast success to set up a third-round trip to West Brom.

Frank, who made six changes ahead of Saturday's visit of Huddersfield, has urged his squad to take belief from their cup exploits.

"I think it was a strong performance against a full-strength Southampton team, which makes it even more impressive," said Frank.

"It was a performance where we definitely showed we can compete with a Premier League opponent.

"But we all know that we need to do that more than one game to go forward. And it's very important for me to mention that.

"We are very pleased. Wins give more confidence – that's why I am pleased we progressed – and this win, this performance and this feeling we need to take into the game on Saturday."

Denmark international Norgaard nodded the visitors ahead with his first goal for the club from a 40th-minute corner, before England Under-21 international Dasilva finished a flowing team move to double the advantage in first-half stoppage time.

In addition to making a large number of changes, Frank named only five of the seven permitted substitutes for the game after an unnamed player tested positive for Covid-19 following a B team fixture on Monday.

Government guidelines have forced some of the club's players into self-isolation, although the Danish coach played down the significance of the off-field circumstances.

"I would not say it disrupted it too much," he said.

"Of course, it affected that we only had 16 for the game today.

"We could have also named some of the players that played on Saturday, but for various reasons we didn't do that because of different training situations and where they are in terms of fitness and stuff like that.

"It disrupted us a tiny bit but not too much."

Saints boss Ralph Hasenhuttl admits his side performed well below their best and require significant improvement.

The Austrian opted for just one change from the team beaten at Crystal Palace on Saturday as he seeks to get his players up to speed following a short pre-season.

"I think at the moment it is a very clear picture that we showed. We have to be very, very clear that at the moment, with the team we have, it will be very difficult to win games," said Hasenhuttl.

"We were not quick enough at any part, not physically and not mentally.

"This is definitely something that we should work on. We played too slow and we did not do enough with the ball.

"Some of our players are not as strong as we have seen them in the past. We have a few big problems but we know that it is a tough season and a long season and we have to get back to working well.

"There is definitely a lot of work to do."