Jeacock, 19, who kept £2million arrival Etheridge on the bench, made a stunning double save in the second half after denying Bryan Mbeumo before the break.

Karanka says he had full belief in Jeacock, with Etheridge not arriving until the day before the game and second choice Andres Prieto having injured his calf in training on Friday.

"I met Zach one month ago and he is calm and confident," said Karanka.

"Even if he is nervous, you can't feel it. Neil arrived yesterday and didn't know his team-mates.

"For sure he (Etheridge) will play, but today I didn't have any doubts that Zach wouldn't be our keeper.

"He is on the pitch like he is on the training ground, and he has a very bright future.

"But we can't make the mistake to think he's ready. He needs to improve and we're well covered with Neil and Andres, but I'm not going to tell you that after an amazing performance the keeper is going to go out on loan!"

Last week, after exiting the Carabao Cup to Sky Bet League Two side Cambridge, Karanka said he needed to change the mentality.

A week on, and with five new arrivals in the team, he praised their commitment.

"I think the first step was to show that commitment on the pitch," he added.

"The five players who weren't here last season, and the six who were, were terrific. They were really hungry."

Karanka was also delighted with Jeremie Bela's goal after the winger headed in a near-post corner in the 37th minute.

"It's something we work on – set-pieces – in training, and if the players see something that works in a game, it helps their belief," he said.

Brentford hit the woodwork twice through Josh Dasilva and Sergi Canos as Blues hung on for their first win in 17 games.

Bees manager Thomas Frank felt his side deserved to win.

"We were patient and quick enough to produce enough crosses, we were dangerous at set-pieces and we definitely should have got the equaliser," he said.

"So 100 per cent we deserved to win. But if we play like that, we will win more than we will lose."

Brentford were beaten finalists in the play-off final against Fulham just five weeks ago, but Frank feels his side have put that behind them.

"I think in football you have to manage expectations and manage emotions, but if you look at clear chances we were more or less on it," he said.

"So in a word, no. If you look at our pre-season games against Derby and against West Ham, we played a really good game and we played well against Oxford and Wycombe, so no.

"They are hungry and they're looking forwards."