The Scottish champions had to come from a goal down in the first leg at Parkhead on Wednesday night, with former Scunthorpe striker Hooper levelling before Charlie Mulgrew's winner.
It was Celtic's first competitive game of the season, compared to Helsinki's 20th, and Hooper is confident Saturday's Scottish Premier League game against Aberdeen will help build match sharpness ahead of next week's return leg in the Finish capital.
"We have got an SPL game with Aberdeen and take the sharpness out of that into Wednesday," he said.
"We have just got to play like we did. We will not sit in and defend, we will go there and play football.
"We have enough attacking players to score goals. We are good on the counter-attack.
"I look to score in every game and if the chances come like they did in the first leg then I think we have a good chance."