The game was just 43 minutes old when Northampton referee Andrew Woolmer, who had already annoyed both sides with some poor decisions, showed a second yellow card to Blackpool striker Tommy Wright for a clash with a Brentford defender.
Wright's first offence - a mis-timed tackle - had looked like a harsh booking and Woolmer won few friends at Bloomfield Road during a game in which he was at the centre of attention far too often.
Blackpool could have gone ahead after just five minutes when Wright, who looked lively before his dismissal, broke down the right and crossed for his unmarked strike partner Matthew Blinkhorn to put his header well wide when he looked capable of opening the scoring.
On 21 minutes Brentford had their first opportunities with Jay Tabb putting a long-range effort just wide from the edge of the area and Lloyd Owusu heading straight at Les Pogliacomi who hardly put a foot wrong all game.
After the sending off Brentford dominated possession for large periods and had their best chance two minutes after the break when Isaiah Rankin's header hit the angle of bar and post with Pogliacomi seemingly beaten.
Blackpool enjoyed their best spell of the game in the last 10 minutes as teenage winger Simon Wiles became more of an influence against a tiring Bees defence.
Wiles and Mark McGregor saw efforts cleared off the line before Wiles created the best chance of the game with five minutes left on the clock.
The young winger broke down the right flank before pulling across a ball for substitute strike John Murphy to head towards goal but his effort was well saved by Stuart Nelson.