Mark Warburton still holds "affection" for Brentford but insists his focus is on getting one over his former club in Monday's west London derby and lifting QPR back into the play-off places.
The 57-year-old started his managerial career at Griffin Park, leading the Bees to promotion from League One in 2013-14 and a place in the Championship play-offs the following year.
Warburton admits he is indebted to Brentford owner Matthew Benham for giving him his chance in management, but he is now fully committed to bitter rivals QPR.
"I had almost five fantastic years there and I'm sure the QPR fans know I'm very aware of the relationship (between the clubs) – there's no love lost," Warburton told the Hoops' website.
"I understand the local rivalry, I understand fully, and my commitment is 100% with Queens Park Rangers. I'm the manager, I want nothing more than a win on Monday night but it doesn't take away from the fact that I had five great years.
"I was given a fantastic opportunity by Matthew, for whom I have enormous respect and a lot of friends still at the club, so for me it's a special game because for both clubs it means so much.
"My loyalty now is with QPR but the affection for Brentford and in terms of what it did for me will never go away."
Rangers have won five of their last eight Sky Bet Championship matches, while the Bees go into the game on the back of successive victories against Millwall and Swansea.
The R's have yet to keep a clean sheet this season, while Brentford have scored six goals in their last two matches.
For that reason, Bees boss Thomas Frank is expecting "a very interesting game", and he said: "They know (how big a game it is) and we will reinforce it to them and definitely when they step onto the pitch they will feel the atmosphere from the first second of the game.
"We know it's a local west London derby...so keeping the momentum with another win would mean everything to us. It could be a very interesting game – 3-4, I would take that result!
"Big credit to Mark, he has done a good job going into QPR – the so-called experts before the season didn't fancy them that much and so far they are near the top of the table.
"Our fans might not like him that much because he went to QPR but I think we need to look at the good job he did here.
"He got us promoted and into the play-offs, so I can only praise him for that and the things he has done for QPR so far."
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