Having enjoyed a full preseason, the Germany striker scored again in the friendly shootout win against Lille.
“It was a good day on Saturday,” he told whufc.com. “I'm very proud of the team. We did a great job and we never gave up.
“We had good mentality, good mindset. The players who came on the pitch, they did a good job. They brought new energy on the pitch.
“I'm very happy with the team and what we achieved.”
Fullkrug added: "For us, the most important thing is the team. I think that's also what changed to the last year.
“We don't need to speak so much about players, if I score, if Jarrod (Bowen) scores, if Malick (Diouf) assists. We as a team did a great job, everyone. That's the most important and that's what the atmosphere is right now on the team.
“It helps us to be successful, for sure.”