Cole Palmer also struck as the Blues were comfortable 3-0 winners at London stadium on Saturday.
Jackson later said, "I try to play for the team every game. I scored two and I am happy - we won which is most important.
"We controlled the game early. Always the keepers go one side and it was a good finish (for his opening goal).
"Plenty of talk and I have been injured for two months, I come back fresh and I hope to get more.
"I am trying to work hard and do more than last year."
He added, "I'm growing higher with my team-mates, they help me a lot and they have confidence in me.
"We keep going. This one is finished and next week we go onto another one.
"The most important thing is for the team to win.
"I am happy to play always. To fight for the team and the team to win is the most important thing."