Barthel was just overmatched and suffocated!
Maybe you can say that about Petra's first match (variety of shots, net approaches), etc, a bit lacking. However, Petra used her slices through out the match (including defensive ones). She put a lot of work on the ball (including hitting at angles, more topspin), when she was on the run and defensively. Petra hit some exquisite drop shots. She was 10/11 on her net approaches. She hit hard ground strokes and winners off both wings. And she moved the ball around the service box quite well with work on the ball.
What match were you watching/What else did you require!?
Remember, this was only her second match (You would like to think, Petra gets better and more confident the deeper she goes at Wimby), and the entire match lasted only 55 min. The last game soaked up 10 minutes of that game time (aka Barthel's last stand/Bagel Nosh). So, you were only going to see but so much. However, what Kvitova showed was excellent and well rounded...Not much to knock in this match.
Hope she continues this, gets better, and keep the calmness and confidence.