With just 60 seconds left Beckett, who had been quiet all afternoon, pounced onto a long ball to fire in from six yards for his third goal of the season.
Brentford striker Jo Kuffour looked to have wrapped up a win for the home side when he scored what looked like the winner just seconds before Beckett's strike.
In a game which matched last season's play-off semi-final losers, defences were on top, Huddersfield looked the more controlled side and created the better openings in the first half.
Beckett should have worked the keeper with a header on 18 minutes from a Danny Adams cross but saw his header flash wide of the post.
The home side responded with a speculative Thomas Pinault volley from 35 yards out which sailed over the bar and Adam Griffiths rose to head a Paul Brooker free kick wide.
The visitors finished the half on top when good work from Danny Schofield down the left caused havoc and his pull back was eventually cleared by Griffiths.
Brentford took control straight from the half time whistle and should have taken the lead with three chances in a five minute period.
Chris Moore forced a save from keeper Matt Glennon with a cross-shot and then Oli Skulason squandered two guilt edge chances.
His first miss was from a cross from Kuffour, which he headed wide from eight yards, and then after some great approach play from Moore the midfielder headed straight at Glennon when it seemed easier to score.
Beckett was denied an opening goal when his 66th minute effort was blocked from close range by Keeper Stuart Nelson.
And that save proved to be crucial as Brentford took the lead on 70 minutes when Brooker's free kick from the left was headed in by the unmarked Kuffour for his first ever Brentford goal.
But the home side's lead lasted all of 90 seconds when O'Connor's attempted clearance hit fellow defender Matt Haywood and went straight to Schofield who made no mistake from six yards.
A long throw from Nathan Clarke almost set up a winner for the visitors five minutes from time. Andy Booth rose highest in the box to connect with the throw, only for O'Connor to clear off the line.
But with just 60 seconds to go, Kuffour pounced to put Brentford back in front. Substitute Alex Rhodes provided the cross and the former Torquay striker out muscled keeper Glennon before firing into an empty net.
However Beckett's effort meant the Terriers snatched a share of the spoils at the death.