Breanna Stewart didn’t feel the need to give Leonie Fiebich a pep talk.

The rookie may have been making her playoff debut in a starting role, but she had plenty of experience in pressurized situations overseas.

“I didn’t say anything to Leo because I didn’t think she needed it,” the Liberty star Stewart said.

She was right.

Fiebich shined in her new role.

The 24-year-old German forward scored a game-high, and career-best, 21 points and sank four 3-pointers, helping the Liberty to an 83-69 Game 1 rout of the Dream in the opening-round playoff series at Barclays Center.

The 6-foot-4 Fiebich started 15 games during the regular season but only when the Liberty were short-handed due to injuries.

Coach Sandy Brondello made the change Sunday, moving guard Courtney Vandersloot to the bench to give the Liberty more size in their starting lineup.

“Leo had a great game. We’ve bragged about her contributions all season long,” Brondello said. “It’s a no-brainer, but she always stays ready. Regardless of starting or coming off the bench, she’s always locked in.”

Fiebich got the news Saturday during practice.

She took it in stride and did her best not to change anything.

She didn’t seem nervous.

Fiebich hit her first five shots, helping the Liberty build a big early lead.

“It just helped that I was in that role a couple of weeks ago,” she said. “I started for this team already. So I didn’t feel super nervous because of that. That helped for sure.

“I kind of try to live in the moment, and I was just happy we moved the ball and my teammates found me. They’re leaving me open a little bit. They have to guard everybody else on my team — we have great players. I can take advantage of that. Obviously, it helps if you see your first ones go in.”