Neath coach Horgan expects big things from the wing but admits he may have played his last game for the Welsh All Blacks before stepping up to the regional game.
"He showed his quality when he got the ball in his hands because there are not many players in the Premiership who could have finished that," said Horgan.
"I'm not sure how many more times he is going to wear a black jersey because I think he is going to be one that's fast-tracked into the Ospreys.
"But all the best to him, it's fantastic that he's been called up to Wales because he's a great kid.
"He has the same personality as Leigh Halfpenny and when I coached Leigh at under-20 level, I can see Daf is up there where he was, so I expect big things from him.
"He is the type of player who with better players around him will progress even quicker and I really hope he goes to Japan."
Howells' first-half effort had given Neath a surprise 13-9 lead against Pontypridd but the runaway Premiership leaders fought back.
Chris Clayton grabbed a brace and a late score from replacement hooker Darren Harris put the result out of reach.
Four penalties and a conversion from Ponty fly-half Dai Flanagan and a further penalty and conversion from replacement No. 10 Simon Humberstone were enough to give Dale McIntosh's side a convincing win and keep their hopes of a first league and cup double alive.
Neath missed a succession of costly shots at goal but Horgan has backed Dai Langon to bounce back.
"We're disappointed, but perhaps we've got ourselves to blame because we shot ourselves in the foot," added Horgan.
"Ponty dominated the contact area, but I can't understand how so many bodies can be on the floor in a ruck situation without giving a penalty away.
"But in fairness to Ponty they played the referee's interpretation better than we did.
"It could have been different, we could have gone seven points up and we knew if we were going to win this game that we needed to take all our opportunities to score.
"We missed nine points and I had a No. 10 in the changing room in tears.
"But Dai Langdon has been a huge player for Neath and I've got huge admiration for him.
"It's a 15-man game and everybody has to take responsibility."