The Norwegian international scored the vital opener against the Second Division battlers in the Worthington Cup second round, second leg encounter at the Lane.
It was our first goal since Sol Campbell's towering header against West Ham fully 346 minutes previously.
Not that it was from lack of trying. Goalkeepers denied us at Charlton, the first leg at Brentford and against Manchester City on Saturday and it was no surprise to see Bees' excellent Olafur Gottskalksson on top form again.
Gottskalksson denied Leonhardsen on numerous occasions at Griffin Park and had to be at his best to divert Steffen Iversen's effort in the first half but finally Leonhardsen beat the Icelandic star after 52 minutes, sliding home having latched onto Tim Sherwood's header.
The battle continued after the goal and having saved a one-on-one chance from Leonhardsen, Gottskalksson could only look on as his fine save from the same player landed at the feet of Iversen for the second goal.
But the first goal was the key. Leonhardsen reflected: "We had a few chances but it was important to get that first goal.
"We had a lot of the ball and it's difficult against teams like that. They were defending with 11 men. But we've got through and that's all that really matters.
"I've had a few chances in games before that and it was and important goal. It made it much easier for us. I'm pleased to score and it's just nice to be involved."
To listen to Oyvind Leonhardsen's thoughts, click here
Oyvind Leonhardsen ended our barren goalscoring run - and ended Brentford's resistance on Tuesday night.