While the striker pushed for the Bees to sell him to Newcastle United before Monday's transfer deadline fell, Giles insists he left on good terms.
“It’s been an interesting last few days and in fact, an interesting last few weeks,” Giles told the club's website.
“The big story is selling Yoane Wissa. He was a fantastic player for us, started off playing wide and evolved to take on the no.9 position and had a brilliant season last year.
“He was a really good, infectious character who was positive around the players and the fans. I personally liked him a lot as well, so there’s nothing but positive things to say about his performances on the pitch for us.
“Transfers are always complicated. There’s always a little bit of emotion, friction and dialogue. That normally stays in house but obviously this one spilled out. It’s not the only one this summer that has spilled out a little bit more into the public domain which is, from my point of view, not ideal.
“Nevertheless, it happened and we had to manage that. For me, fundamentally, when you have to make a decision about transfers, and complicated decisions - decisions which are impactful on the pitch and also off the pitch in terms of the club’s whole overall position - you need to stay focused on what is the right decision for the club, not whether it’s in public or not in public.
“You have got to take the emotions out of it and got to ultimately make the decisions for the club. Every decision I make or we make collectively during a transfer window will strip all of the emotion out of it and focus purely on what is the right decision in this moment in time for the club overall."