Thomas Frank struggled to put his finger on the reasons behind Brentford’s lack of cutting edge after a goalless draw against Birmingham which saw his side lose further ground in the automatic promotion race.

The Bees’ fourth consecutive draw has left them nine points behind second-placed Watford, albeit with a game in hand, and Frank’s previously free-scoring side have found the net just five times in their last six matches.

They found a visiting goalkeeper in fine form on Tuesday night, Neil Etheridge denying Ivan Toney in either half and saving well from Bryan Mbeumo’s header, and couldn’t break down the relegation-threatened Blues.

“It was a good first half, we moved the ball well and created some big chances,” Frank said.

“We were less good in the second half. We didn’t show enough quality on the ball in terms of finding the openings. I saw a lot of will and determination from the players but not the cutting edge.

"The first goal would have been so important for us but it's also key for us to look at performances and they haven't been bad. Is it quality, fine margins, coincidence, confidence or luck?

“I'm not sure but we are not quite the well-oiled machine that destroyed everything in that 21-game unbeaten run."

The hosts survived an early scare at the Community Stadium as Gary Gardner’s close-range effort came back off the post.

Brentford went on to dominate possession and saw Mathias Jensen and Sergi Canos pass up presentable opportunities before the break.

The second half began with a penalty appeal turned down early when Mads Roerslev went down in the box but the protests fell on deaf ears and the stalemate remained.

“Birmingham came here with one aim, which is fine as they are fighting to stay up, and it’s up to us to take the initiative,” Frank said.

“Without the first goal, we were getting impatient and rushing towards the end. We need to stay cool in the final third and we should have created more dangerous situations.

“It is a snapshot of the season. It was OK, fine, but not top in the final third. There were better moments against Huddersfield and Nottingham Forest was really good.

“We are not far away but we are lacking that consistency in the final third at this moment in time.”

The stalemate means just five points now separate the Bees from seventh-placed Bournemouth, causing a worry that Frank’s side could end up looking over their shoulders rather than targeting the top two should they keep dropping points.

Next up for the Bees is a trip to managerless Preston on Saturday.