The obstacle discipline was included for the first time as the International Modern Pentathlon Union seeks to have it replace equestrian in its events.

Unterberger prevailed in a tense women's contest just five points ahead of Poland's Katarzyna Dębska on 1,407 points in the Lithuanian town of Druskininkai.

France's Louison Cazaly's 1,389 total was just enough to see her clinch bronze.

Unterberger finished some way off the top of the pack in the fencing and swimming elements, with respective finishes of seventh and 21st.

However, second-place results in obstacle and laser run ensured she stood atop the podium.

"It feels amazing because I am still under 19, probably, and at the European Junior Championships I already won silver, but then here my fencing was pretty bad, so I'm so happy that I had the chance to compete here and this is the outcome," Unterberger said.

"Obstacle is definitely a difficult challenge because in the semi-final, I fell two times and was eliminated.

"I was a bit too hectic and today I slowed it down and managed quite a good time.

"But it's definitely still a hard discipline and we have to do a lot of training."

Rochat amassed 1,539 points to top the men's standings as Lithuanian Paulius Vagnorius was caught in a French sandwich with Leo Bories coming third.

Bories' 1,526 saw him just one point show of Vagnorius' total.

"It's unbelievable for me," Rochat said after his win.

"All the things I have been through this year, with a new environment, new coaches, everything - and it worked so well because now I am world champion.

"I'm so grateful to everybody.

"Next year I will be a senior and I think I will need a lot of confidence for the future, to manage to follow the best athletes in the world.

"It's thrilling for me to think about next year." 

Amer and Mohamad were the victors on the final day of competition in Lithuania following a stunning all-round performance.

They were the best pair in fencing and swimming, and finished third and fourth in obstacle and swimming, respectively.

It resulted in them notching up 1,353 points to beat Unterberger and her fellow German Moriz Klinkert by 20.

Vagnorius also podiumed for the second time in third alongside compatriot Elzbieta Adomaitytė on 1,315 points.