Glasgow scored the game's first try, but Scarlets took control of the game to leave Scotstoun with a comfortable victory.
Speaking to glasgowwarriors.org, Gregor said: "The result is disappointing. It was a combination of some bad luck and some inaccuracies we have to work on.
"We weren't able to build on a lot of the positive work from early in the match and Scarlets had a foothold on the game from the way they defended and they slowed our ball down.
"They turned us over on too many occasions for our liking and we were never able to shake them off.
"There was a lot of effort put in which is pleasing. There were some really good individual performances, people who put in huge effort throughout the game.
"D'arcy Rae worked really hard in the scrum, Brian Alainu'uese carried really strongly throughout the game, Adam Ashe had a number of carries and in the backs Nick Grigg, Peter Murchie and Rory Hughes all stood out.
"There was a lot of effort in the game and a lot of effort from players that haven't played much this season so that's a real positive.
"The players took the game to Scarlets. We have things to work on, we have got a massive game on Saturday and we know around the breakdown, an area we really pride ourselves on, we have to be better."
Next up for the Warriors is Ulster in Belfast with extra incentive on a victory having dropped out of the play-off places following Friday's defeat and Townsend believes the Scarlets experience will benefit his players.
He said: "I think we will be more focused on dealing with threats from the opposition, whether that is targeting our ball when we're attacking or the opposition when they have the ball.
"Those are the two areas we will have to work on but there was a lot of good things, some of our defence in the first-half was excellent.
"We're disappointed as a group to lose in front of our home supporters and to lose in such an important game when you're playing against someone just behind you in the league.
"Now we're behind them and we have to take the effort but improve the accuracy and go to Ulster and give it everything."