The 32-year-old made his Pompey debut at the weekend during the 2-0 defeat to Bournemouth - a result that extended the club's winless run to 19 games.
It is the club's worst run of results in their history and they will go bottom of the League One table if they lose to John Hughes' side at Victoria Park on Tuesday.
But Agyemang believes Pompey showed signs of ending their abysmal run against the promotion-chasing Cherries on Saturday and can cause Pools some problems.
He told the club's official website: "It's frustrating (to lose) as we working so hard to get something from the game and from the moment they scored, it was obviously going to be a lot tougher for us.
"We created more chances and looked the better team at the hour mark. Then they scored and I thought it would be a lot more difficult.
"We had to try to open up a bit more and commit players forward, but that meant we were susceptible to conceding more goals.
"But I felt it was a good performance and yet a disappointing result.
"But if we produce a similar display at Hartlepool then a good result certainly isn't beyond us."