TROMSØ, Norway (Interstat) — Ruben Jenssen’s goal in the fourth minute was all Tromsø needed to secure a 1-0 victory over rival Rosenborg in the Eliteserien on Saturday, defying pregame projections and kicking off the Norwegian top-flight season with a significant upset at a frigid Romssa Arena.

The match, played in sub-zero temperatures, was decided almost immediately as the home side capitalized on early momentum. The lone score came from a well-worked team move that was finished by the veteran midfielder, setting a defensive tone that Tromsø maintained for the remainder of the contest.

The decisive play developed quickly after kickoff. Defender Alexander Warneryd initiated the attack, pushing forward from his backline position to find midfielder Vetle Skjærvik. Skjærvik then played an incisive pass to forward Vegard Erlien, who drew multiple defenders before laying the ball off for the onrushing Ruben Jenssen. The Tromsø captain struck his shot cleanly from the edge of the area, beating the Rosenborg goalkeeper and sending the home crowd into an early frenzy.

That early strike forced Rosenborg, a traditional powerhouse in Norwegian football, to chase the game. The visitors controlled large stretches of possession but struggled to break down a disciplined and resolute Tromsø defense. The home side’s compact shape and relentless work rate frustrated Rosenborg’s attackers, limiting them to few clear-cut chances throughout the 90 minutes.

The physical nature of the match was reflected in the officiating, with six yellow cards issued by the referee. Tromsø’s Skjærvik was booked in the 25th minute for a tactical foul, one of three first-half cautions for the home side that included Erlien and Warneryd. Rosenborg’s frustrations also began to show, with substitute Ole Kristian Selnæs receiving a yellow card shortly after his introduction in the 29th minute. The card tally was rounded out in the final minute of regulation when Tromsø substitute Ulrik Jenssen was booked.

Tromsø’s victory marks a perfect start to their Eliteserien campaign, moving their record to one win and zero losses. For Rosenborg, the loss is an inauspicious beginning, leaving them with a record of zero wins and one loss. The result is identical for both clubs across all competitions for the nascent season.

The outcome was a stark contrast to statistical forecasts. According to Interstat’s game simulator, the match was projected to finish with a 2-1 victory for Rosenborg. Furthermore, the same organization’s ELO rating system had given Rosenborg a 62 percent probability of winning the contest, underscoring the magnitude of Tromsø’s triumph against the odds.

The three points earned in this northern Norway derby provide Tromsø with crucial early-season momentum, while Rosenborg is left to regroup after a performance that failed to live up to its pregame favoritism.