The victory avenged the 18-10 defeat in Belfast last year and stretched Townsend's side's winning streak to six games.
For Ulster it was only the third league defeat of the season and it trims their advantage at the summit to just three points, not that Townsend is getting carried away just yet.
"We've just got to keep on producing the results and aim for a home semi-final" said Townsend.
"I was living every moment of that last 20 minutes. What an effort from the players. I'm so proud.
"At the end, they were hanging on. They wanted that win and they fought every inch for it.
"Last week I was really proud of the team because players that hadn't been getting opportunities and they stepped up and played really well and now I'm really proud of the character.
"Our ambition was really good. We ended up with four tries, could've had a couple more so that's great for the league table.
"It brings Ulster back into the mix. We're now three points behind them so getting the bonus point was crucial and we've got some big games coming up; we play six of the top seven teams.
"We've just got to keep on producing the results and aim for a home semi-final."