The Swedish striker set up Noni Madueke for the opening goal before scoring himself shortly before half-time in Wednesday's victory in Prague. It was another encouraging contribution from the Arsenal forward, who has now recorded five goal involvements in his last five matches.
Gyökeres produced an excellent through ball for Madueke to open the scoring, then finished confidently to give Mikel Arteta's side a two-goal advantage at the break.
Although Slavia fought back after half-time and made the closing stages uncomfortable for the visitors, Arsenal held on to collect their third win in four Champions League matches.
"I'm feeling very good. Obviously, I'm happy with the win and to contribute to the two goals," Gyökeres said.
"So, a good feeling in the first half - and then obviously in the second half, with how that went, maybe the feeling isn't as good right now. But overall, if you look at the first half, it's a good feeling."
The forward was pleased with his involvement in both goals and believes contributing regularly in attack is an important part of his responsibility.
"It's my job as a striker and of course I want to contribute every game when I'm on the pitch and want to be involved as much as I can in attacks. Today felt very good, like I said, especially in the first half."
Gyökeres' performance was particularly welcome as Arsenal continue to balance their domestic and European commitments. The striker has not started every match, but made the most of his opportunity in Prague.
The result leaves Arsenal with 10 points from their opening four Champions League fixtures and in third place in the league-phase table.
Gyökeres is pleased with the team's progress but believes there is still room for improvement.
"So far we've had a good run in the Champions League and in the league as well.
"At the stage we're in right now, we're in a good spot, but I think we're all clear on what we can improve and what we need to do to take the next step."