Reflecting on the 16-13 win, Marshall said: "It was a scrappy game and both teams didn't really play well. We didn't threaten enough in attack but I thought we scrambled well in attack."
His sharp reactions were the difference between the two sides as he dived over with just five minutes remaining, but he was quick to praise his team-mates for their contributions to his ninth try in Ulster colours.
"I didn't have much to do for the try. I just squeezed over the line when John (Afoa) was brought down just short. It was a good team try and it shows what we are capable of producing.
"We didn't play very well but I thought we showed great character in the second half and the most important thing is that we got the win and it keeps us on track."
Marshall, who was an unused member of the Ireland squad that toured New Zealand in June, underwent surgery on an elbow injury during the summer which affected his pre-season preparations.
But he is feeling fit and is delighted to be back in action, stating: "Injury-wise I feel good, my elbow isn't giving me much trouble at all. It was good for me to get back on the pitch.
"I got 20 minutes last week (against Glasgow Warriors) and another 40 on Saturday night so its good to catch up a bit with the players who have had more game-time."
He admits Ulster will have to improve vastly if they are to beat Munster, who also boast two league wins, at Ravenhill on Friday.
"Friday's game will be a really tough encounter as all the interpros are. I'm assuming they will come up to Belfast with their full contingent of internationals and we will have a couple more back as well.
"We will have to be firing on all cylinders if we are to come away with another win, a performance like the one on Saturday night won't be good enough. It's our first interpro of the season so it's exciting for the fans, but also the players."
With Conor Murray likely to line out for Munster on Friday night, Marshall may get the ideal opportunity to stake his claim for a call-up for the GUINNESS Series in November, yet he insists his priority at this stage is getting into the Ulster team and the 27-year-old is not worrying about Ireland selection.
"I'm expecting Conor Murray to play on Friday night and he's currently the number 1 scrum half in Ireland, so it will be a big test if I'm selected. But the main thing for me is getting more game-time with Ulster.
"Blane McIlroy and Michael Heaney have been playing well so my focus, first and foremost, is to fight for a place in the Ulster team."