Marti finished with two goals and three assists as Switzerland defeated Germany, 7-3, in the second contest of a best-of-three relegation series.
Switzerland retains its spot in the top division, while Germany will compete in Division I in 2023.
"I think we have good young players coming up," Marti said. "Obviously our goal was the quarterfinals. We didn't reach that, but the next generation coming up can reach that. It's important for the development for the whole country."
With her five points, the 18-year-old came within one of matching the all-time tournament record for points in a game.
The feat has been accomplished just three times since the event began in 2008. United States' Haley Skarupa registered the last instance with two goals and four assists against Czechia on March 30, 2010.
"I didn't know," Marti said of the record. "But I was trying to score (at the end)."
The native of Bleienbach finishes her career at the U18 level with four goals and five assists in 10 contests between 2020 and 2022. Up next for the member of Switzerland's Olympic and senior women's team is to make a decision on where to play in college.
"It's my goal to come here and play at the next level," she said. "I will see what time brings."
Margaux Favre made 15 saves to earn her second victory of the tournament.
Marti picked up her first point on the power play 4:33 into the contest. Alena Rossel cut off Marti's pass in the slot and took advantage of traffic in front to beat German goaltender Felicity Luby on the right side.
Alessia Baechler doubled Switzerland's lead at 13:50. Using forward Renee Lendi as a screen, Baechler took a pass from Nina Harju at the top of the right circle and fired it past Luby. Marti picked up the secondary assist on the play.
Marti scored her first of the afternoon — a shorthanded tally — with 10 seconds remaining in the first period. With the Germans caught in a slow line change, Marti converted on a 2-on-0 when she one-timed a Chiara Eggli pass from the right faceoff circle.
"I've been struggling the whole tournament to score," Marti said. "I had a little bit of luck, but that was the breaking point where I started to score."
She tacked on another just over three minutes into the second period from the bottom of the left circle to make it 4-0.
"It was a 2-on-1 and thought I could pass it, but thought Germany's defense might get it, so I just shot it and it went in," she said.
Jade Surdez gave the Swiss a five-goal cushion at 5:49 of the middle stanza, chasing Luby from the net. She finished with seven saves in just under 26 minutes of play.
Eva Bargo Cuns and Eggli also scored for the Swiss, who finished the event with a 3-2 record. Anastasia Gruss, Lola Liang and Anna Rose scored third-period goals for the Germans.
Chiara Schultes, 16, made her tournament debut and made 12 saves down the stretch. She was added to the German roster after Sara Brammen suffered an injury.