MIAMI (AP) — After a disappointing showing on the first day of the Race of Champions, Sebastian Vettel bounced back in a big way.

Vettel single-handedly won the Nations Cup for Germany, winning all eight of his races while beating United States NASCAR drivers and brothers Kurt and Kyle Busch in the final.

"We didn't get to race against each other, so we still don't know who the better 'Busch' is," Kurt Busch said, "but we know Vettel can whack two Busches in one day."

Vettel, a four-time Formula 1 world champion, was knocked out in the group stage in Saturday's individual event as Juan Pablo Montoya won the Champion of Champions.

"The bigger trophy was there yesterday for grabs, but (I didn't win), so I wanted to make sure I didn't leave empty-handed," Vettel said.

There were supposed to be 10 two-driver teams in the Nations Cup, but Pascal Wehrlein was unable to compete with Vettel after getting into a crash Saturday and being held out as a precautionary on doctor's advice, leaving Vettel to handle the responsibility of driving each race for Germany.

"Maybe it helped after yesterday to take it a bit more serious," Vettel said. "I started off on the wrong foot, so the day was very short for me. Today, I just wanted to get some time on the track and it obviously worked out very well, but it would have been nicer to share it with Pascal."

Vettel edged Montoya in the first semifinal race ending Montoya's run of winning nine consecutive races over two days.

Kurt and Kyle Busch beat Team USA IndyCar drivers Alexander Rossi and Ryan Hunter-Reay in the semifinals. Kurt Busch slipped by Rossi in the deciding race.

"It was an honor to go out there and race for the United States along with my little brother Kyle," Kurt Busch said. "To advance out of the group as the NASCAR group, we definitely wanted to do that ahead of the IndyCar guys and the Rally Car guys."

It was a unique experience for the Busch brothers who race for different teams on the NASCAR circuit.

"I had a super time, a lot of fun, to be teamed up with Kurt there, but also yesterday to beat some of these guys from around the world in all different kinds of cars was exciting for me," Kyle Busch said.

Petter Solberg gave the World Team a win over America in the final race of a 10-race event to conclude the day. Solberg was aggressive on the track driving the RX Supercar Lite to beat Scott Speed.

"Scott Speed came to me and said, 'I'm going to beat you,'" Solberg said. "I was thinking, 'OK, you can try.' So I was really focused and went out proper around the start. I felt really good and was really happy."

The Polaris Slingshot SLR was involved in its second crash in as many days when Gabriel Glusman lost control on the final turn and bounced into two barriers before coming to a stop ending his day.

Wehrlein flipped over a barrier and landed upside down on a concrete wall in the Slingshot on Saturday.