The Woking-based squad ended the 2019 season as the leading midfield team, beating the competition to fourth place in the constructors' standings - its best championship result since 2012.
However, the team was quick to point out weaknesses that could be improved upon and aimed to address them for the 2020 campaign.
With the season now set to begin in Austria in two weeks following a lengthy delay due to the coronavirus pandemic, Seidl says McLaren showed positive signs at Barcelona in February but is wary of gains from rival teams.
“One thing that was clear in this two and a half month break is there's a reason why we wake up every morning as racers,” Seidl said in a video via the McLaren app.
“The longer the break was and the longer we were away from racing, the desire to go back to racing and competition, measure ourselves against the best in the sport is bigger and bigger every day.
“I can assure you that me personally, and everyone in the entire team, we are really pumped up now to get back to Austria and see where we are.
“We know from winter testing that we definitely made a good step over winter. We had a good test [but] at the same time, the competition around us did a great job as well.
“So it's important now to get back to this momentum we had over winter as quickly as possible, get back into this competition moe, this fighting spirit. Hopefully, we have a good start.”
During the lockdown period in place across the world due to COVID-19, it emerged that McLaren would cut 1,200 jobs from its group, including 70 from its F1 division.
While Seidl admits it was nice to spend more time with his family, it was difficult to endure the tough decisions that were being made.
“On the F1 side, looking back it was not a nice chapter, I have to be honest,” he said. “We had to do a lot of difficult decisions during this period simply to make sure we get through as a team.
“But looking back I'm happy with the decisions we made, I think we made the right decisions as a team.
“We made a lot of good decisions also together with the other teams, the FIA and Formula 1 for a good future of Formula 1 after the crisis. It was just not nice not being able to communicate these deicisons straight face-to-face to our people.”
Bahrain International Circuit - Winter testing