New loan signing John Bostock scored twice on his début as Brentford shared the points in a wind-swept, rip-roaring, London derby.
The 17-year-old, who signed on loan from Tottenham Hotspur 24 hours before kick off, took just nine minutes to get his name on the score sheet.
And he doubled his tally with what looked set to be the winning goal midway through the half.
The visitors had levelled it up when Paul Robinson headed in from a corner and they earned a point when substitute James Henry curled in a free kick with less than two minutes of normal time remaining.
With conditions far from ideal for playing football - rain earlier in the week left the pitch very boggy and the wind made any aerial pass a lottery - Brentford flew out of the blocks, keen to impose themselves against their high-flying south London opponents.
The predominantly left-footed Bostock, starting on the right of midfield, immediately showed his quality with nice touches and early runs but the first chance of the afternoon fell to Kevin O'Connor, who headed a Danny Foster cross wide.
Moments later Bostock, Marcus Bean and Foster combined to create space for Charlie MacDonald he put in a low cross that Ben Strevens came within a whisker of turning home at the near post, goalkeeper David Forde dived at the feet of the striker to put him off and Alan Dunne whacked the loose ball away.
The goal Brentford had been threatening came when Millwall failed to clear a Ryan Dickson cross and Bostock picked it up inside the area on the right side, he cut back and forced the ball into the corner from 12 yards.
The goal woke Millwall up and they almost grabbed an equaliser when Forde quickly threw out to find Danny Schofield, the winger ran from deep and, as the defence parted in front of him, he smacked a shot from 20 yards against the crossbar.
Brentford failed to clear the danger and Millwall won a corner which Chris Hackett swing over and Robinson headed in on his knees from four yards.
Millwall took command of the game following the goal, without creating much, and it was Brentford who scored the next goal - and it was a bizarre one.
Bostock took a corner from the right and curled it towards the near post, goalkeeper Forde stood and watched as it bent into the net.
Hackett shot wide for the hosts and Foster made a good challenge when Schofield got in behind after a long ball.
Dickson headed a corner over and Jason Price blazed wide at the other end before an entertaining first half was brought to a close.
The second half took a while to get going but Brentford held the upper hand in the early stages, after Dickson has made a good early tackle to deny Neil Harris.
MacDonald fired a shot against the post after a nice move involving Dickson and Strevens, Bostock was unable to turn in the re-bound.
O'Connor had a shot saved and Foster and Strevens had shots blocked before MacDonald was just unable to turn in a Dickson cross.
Schofield curled an effort over and O'Connor headed an Henry corner narrowly over his own bar but MacDonald could have sealed it when he raced onto a Strevens flick but as he prepared to pull the trigger Tony Craig made a great last ditch tackle.
Lewis Price tipped a curling Jimmy Abdou effort over as Millwall put the pressure on and as Robinson headed a corner down Harris was unable to convert from close range.
Wilson made a fine block to deny Steve Morison, Tony Craig headed wide and, from another corner, a Morison effort was blocked on the line.
Just when it seemed Brentford had weathered the storm a curling Henry free kick eluded everyone in the middle and nestled in the bottom corner.
But The Bees reacted strongly and could have won it.
Karleigh Osborne nearly scored the goal of his life when he picked up a free kick and curled an effort against the crossbar from 20 yards - MacDonald's effort from the re-bound was blocked.
Schofield wasted a late chance with a low shot straight at Price as the visitors almost stole it in the dying seconds.
Brentford: Price; Foster (sub Osborne 85 mins), Bennett, Wilson, Dickson; Bostock, Bean, O'Connor, Weston; Strevens, MacDonald
Subs (not used): Moore; Legge, Taylor, Hunt, Wood, Cort
Millwall: Forde; Dunne, Robinson, Craig, Smith (sub Ward 63 mins); Hackett (sub Henry 63 mins), Laird, Abdou, Schofield; Price (sub Morison 78 mins), Harris
Subs (not used): Frampton, Bolder, Martin, Sullivan
Attendance: 6,408 (1,829 away fans)
By Chris Wickham