Brentford's faltering promotion push suffered another setback as Birmingham boosted their Sky Bet Championship survival hopes with a hard-earned point in a 0-0 draw.
The Bees squandered a string of clear-cut chances, with a lack of clinical finishing, quality with the final ball and some brilliant stops from Blues goalkeeper Neil Etheridge costing them dear.
Jonathan Leko could have won it for the visitors with a six-on-four counter-attack and cross-shot deep into injury time that was only blocked by a desperate Brentford leg.
Thomas Frank's side looked a shadow of the free-passing outfit that cut sides to ribbons earlier in the campaign, with confidence in short supply.
Even Ivan Toney's goalscoring touch deserted him as he was offered little protection by the officials from the physical presence of former Bee Harlee Dean and Kristian Pedersen.
Mathias Jensen set the profligate tone for the Bees, turning down a good chance to give his side a dream start six minutes in when he skied Pontus Jansson's pass with the goal gaping.
Birmingham should have taken the lead 10 minutes later when former Bee Scott Hogan's cross-shot found Gary Gardner at the far post but he could only steer his first-time shot against the foot of the post.
The hosts came close on the half hour when Mads Roerslev was inches away from connecting with Bryan Mbeumo's whipped cross at the far post.
Sergi Canos should have broken the deadlock moments later when a superb Vitaly Janelt through-ball sent him free - but his chip over the onrushing Etheridge drifted inches wide.
Top scorer Toney stung Etheridge's fingertips with a blistering 25-yard drive after a neat Canos through-ball, before Jensen's shot after a slick five-man move suffered the same fate a minute later.
Brentford almost carved a way through Blues' resolute defence after the restart but Canos' determined run and pass into the path of Mbeumo was asking too much of the Frenchman and Etheridge was quick off his line.
The 'keeper had to be at his very best seconds later to palm Toney's blistering half volley to safety at full-stretch as the game started to open up.
Birmingham hearts were in mouths in the 65th minute when Canos took Jensen's pass and Marc Roberts' shove sent him flying - but the Birmingham man escaped punishment.
Etheridge had to be at his best again in the 76th minute, going full length to tip Mbeumo's clever glancing header from substitute Emiliano Marcondes' cross past the post.
It was end-to-end stuff as the game closed with Brentford, who have drawn their last four, unable to turn their possession and superior technique into a goal.
What the managers said...
Brentford's Thomas Frank: "The first half was very good and we created lots of chances. If we'd taken one it would have been a completely different game - but we didn't so we are here and it's 0-0.
"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."
Birmingham's Lee Bowyer: "The players got something they deserved through hard work. To come here and take a point from a top side like Brentford is some achievement.
"We were causing them problems at times and they caused us problems, which I knew and expected. But when our keeper was called upon he stepped up and made saves so overall I'd like to think we deserved it. In fact at the end, I thought 'we're going to nick this'."