Pliskova wasted eight set points in the opener but recovered quickly in the following two sets, serving out the contest on Court Philippe-Chatrier after two hours and 15 minutes.
Cedric Bakambu finished second with a stunning strike in the 27th minute after a goal was disallowed for offside in the opening time.
Plzen dominated the second half but Beer Sheva came closer to scoring, as Dutch striker Elton Acolatse hit the post in the 68th minute after a run from the halfway line.
Earlier in the day Suarez scored twice and provided an assist on his Atletico Madrid debut, just four days after arriving from Barcelona as Atletico began their campaign with an impressive 6-1 victory at home to Granada.
The 64-year-old, who began his managerial career as a teenager in 1975, had previous spells as Botafogo boss in 1986, 1995, 1998 and 2001.
Bayern increased the pace and eventually halved the deficit in the 36th minute when Joshua Kimmich curled the ball from 16 meters into the top right corner.
This was Inter's first game of the season, as its clash with Benevento was postponed to September 30.
Some fans and pundits fear Flick could soon be fed up with his side's strategy to avoid costly transfers and follow what many call a healthy spending policy.
A brand-new championship format amid strict epidemic prevention measures brought about unprecedented challenges -- each team been asked to play a game every four days, and even more regularly after the CFA Cup kicked off, which forced many clubs to deal with squads plagued with niggling injuries.
"This is the first major tournament in the last 11 months because of the epidemic. I know I can swim faster this time and want to see how fast I could be," said the bronze medalist of the world championships.
Lautaro Martinez came off the bench to add the fifth for Inter with a rocket in the 72nd minute, and Caprari scored a consolation goal for Benevento four minutes later.