But who are Telstar, and why was their win on Sunday so shocking? Flashscore introduce the newest additions to the Eredivisie to you.
Anonymous
Founded in 1963 after a merger between the professional branches of local clubs VSV and Stormvogels, SC Telstar from Velsen-Zuid quickly entered the Eredivisie after finishing second in their first year in the second tier.
The seaside club remained in the highest division for fourteen years before relegating to the second tier in 1978. In the years following their descent, Telstar yo-yoed between the sub-top and lower regions of the second-division table, finishing fourth, fifth, and sixth in years following one eleventh-place finish and two fifteenth places.
Years of anonymity ensued in Velsen-Zuid, a small village with about 3,000 inhabitants on the outskirts of the port city of IJmuiden. SC Telstar remained in the background during this period and established itself as a local club - a reputation they value highly to this day. "This is the club of fish and steel. This is the club that wins the hearts of football fans in its own unique way."
The club saw some notable names come and go over the years. Think of Louis van Gaal, who played 25 games in Telstar's last season in the Eredivisie, Ruud Geels, the legendary striker who became the Eredivisie's top scorer five times, or Jimmy Floyd Hasselbaink, who started his career at Telstar in 1990.
But all those who loved and supported Telstar, who renamed themselves Stormvogels Telstar (translated: Storm Birds Telstar) between 2001 and 2008, never saw their team reach the highs of the 60s and 70s again. The White Lions fell, and fell hard.
After the early high finishes, Telstar managed to finish in the top 5 just once between 1987 and 2005. For most of the 21st century, Telstar fans were just happy that there was no relegation from the Eerste Divisie, as their team finished in the bottom half 18 times since 2000, 10 of which came consecutively between 2008 and 2017.
Lightning-quick revolution
Telstar were always the funny, enjoyable minnows of the second tier. A lively media presence, a sympathetic club, a press secretary in a wheelchair called Dennis Bliek whose image was used on a poster saying "Stand up if you're a Telstar fan", an outspoken, eccentric director called Pieter de Waard who called his club "the only professional football club with a 20-letter name: Telstarrrrrrrrrrrrrr!"
In the background, Telstar worked on an ambitious plan. Commercial director Steef Hammerstein introduced long-term plans to get Telstar back in the Eredivisie by 2026, when the 1963-born club celebrated its 63rd anniversary.
It seemed farther away than ever when Telstar finished seventeenth in the 2023/24 season. The club fired manager Mike Snoei in February and appointed Anthony Correia as his successor - a move out of confidence and trust.
After playing all his 356 professional games for Telstar, Correia worked as an assistant at Telstar since 2017 and as a manager at amateur sides HSV ODIN'59 and VV Katwijk. With Katwijk, Correia established himself as a talented coach in his own right by winning back-to-back national amateur titles.
The Telstar board entrusted Correia with improving the status quo at Telstar. Still, it's unlikely they thought he'd revolutionise the club this fast, especially after the rough start to their season. Telstar headed into the Christmas break in eleventh after winning just six of their first 20 games.
Amateurs-turned-heroes
However, Correia's team improved and marched up the table. Telstar won 11 of the final 18 games and showcased a fast-paced, attacking style of football under Correia - an impressive feat with a squad mostly made up of former amateurs.
Eight players of Correia's promotion-winning side played for amateur teams before joining Telstar. Three of them - striker Youssef El Kachati, defender Guus Offerhaus, and midfielder Tyrone Owusu - played for Quick Boys, the bitter rivals and noisy neighbours of Correia's former club VV Katwijk. Offerhaus played a vital part in the promotion race by playing 42 out of a possible 44 games, El Kachati led the team with 19 goals and provided six assists, and Owusu was a midfield stalwart in his first season at the professional level.
El Kachati proved especially vital in the play-offs for promotion to the Eredivisie. In the first round, ADO Den Haag were toppled 3-0 over two legs, partially thanks to El Kachati's two goals and his winning goal in The Hague. In the semi-finals, El Kachati scored a vital equaliser in the second leg, forcing extra time in Telstar's final-clinching 2-1 win over FC Den Bosch.
And then, in the finals against Eredivisie side Willem II, El Kachati scored in both legs again as Telstar drew 2-2 before grabbing their crucial 3-1 win in Tilburg.
The unconventional people's club in the Eredivisie
And so Telstar did it. Toppling Willem II in Tilburg to reclaim their spot in the Eredivisie after 47 long years.
No one knows what their squad will look like. Captain Mitch Apau, who became a father 15 hours before clinching promotion with Telstar, recently agreed a deal with amateur side Spakenburg but admitted he's tempted to play Eredivisie football with 'his' Telstar: "I'll think about what I'm going to do. I'd like to go into the Eredivisie with Telstar."
Ronald Koeman Jr., son of the former European champion and current Netherlands manager, also does not know whether or not he'll defend Telstar's white shirt next season. He would not mind playing in the Eredivisie with the club, though. "I don't mind at all. I'm really enjoying myself here."
But for Youssef El Kachati, who's been linked to clubs such as NEC Nijmegen, Schalke 04, Hannover 96, and Celtic, it was clear: he will leave the club. "I knew this would be my last match wearing the Telstar shirt. I had decided to give it my all, even if they had to carry me off the pitch on a stretcher. I had to make it to the Eredivisie with these guys."
He kept his promise, and so we will see Telstar in next year's Eredivisie. The club, who want to be "the unconventional people's club in the Eredivisie", will get to show what they stand for. I'll give the last word to Telstar themselves.
"We are a club of tough men and strong women. IJmuiden is our birthplace, and that makes us unique. We think and act just a little differently. We value openness and honesty. And no one here is more important than our club. Anyone with a good heart is welcome here. Here you feel at home, here we are together. We are committed and fearless. We are the White Lions!"