Brentford fought back from two down to salvage a point in a windswept 2-2 draw with Blackburn at Griffin Park.
And he stretched the advantage after the break when Raya was harshly adjudged to have brought down John Buckley in the box, and he sent him the wrong way from the spot.
That goal sparked a fightback from the Bees who hit back on 62 minutes with the goal of the game, Watkins taking a drilled Henrik Dalsgaard through ball on his chest and smashing home unstoppable volley into the top corner.
Nine minutes later Brentford were level, Lewis Travis again harshly ruled to have tripped Mads Roerslev in the box, with Benrahma doing the honours from the spot.
The visitors managed just one other effort on target in a first half dominated by the hosts, who were repeatedly thwarted by some brilliant last-ditch defending.
After the early opener, Bryan Mbeumo might have given the Bees an immediate response, but his header from a near post corner sailed just wide.
Minutes later Benrahma went close again with a sizzling first time effort after a neat build up down the right, but Walton was again equal to his effort.
Nyambe was a thorn in the side of the Londoners with some brilliant blocks and his best of a prolific first half came when he slid in to block Benrahma's goal-bound drive on the half-hour.
The right-back was in the thick of it again just before the break, again denying Benrahma after the winger cut in from the left and teed up a shot destined for the bottom corner.
Rovers' only other genuine attempt on goal came just before the break after Armstrong had been fouled on the edge by Christian Norgaard, the tricky front man dusting himself down to force a smart save from Raya.
After the break Brentford surged forward with the wind at their backs and created a strong of chances, with Benrahma guilty of some uncharacteristically sloppy finishing.
He skied a 64th-minute effort before Pinnock slashed a half-volley wide and Benrahma's curling drive was palmed clear by Walton as the pressure grew.
Blackburn had a chance to turn the game on its head on 72 minutes when Armstrong raced onto Dalsgaard's poor back pass but was thwarted by a great one on one block by Raya.