The now 34-year-old Alderweireld personally got his current club, Royal Antwerp, the title last summer. He won that prize four times in the Netherlands, together with Ajax, the club where he played in the first team for over four years. "I follow Ajax as much as I can", he says on the phone.
In his Ajax career, Alderweireld played ten Klassiekers. Eight in the competition and two in the Dutch Cup. He did not lose a single one: seven victories and three draws. "I'm lucky to have been on the winning side almost every time; I never lost one. I missed one during an injury, and that’s the one we lost", the defender says, smiling.
Despite his Belgian nationality, Alderweireld grew up with the Klassieker during his time in Amsterdam. "I quickly figured out the importance of that match. I noticed how incredibly important the match was inside and outside the club. They are the two biggest clubs in the Netherlands, and it’s the most beautiful match there is. They are on the cutting edge; that’s what I love."
While strolling through the Albert Heijn, Alderweireld was approached often in the week leading up to the Klassieker. "I lived right outside the city centre and did not come outside often due to our busy schedule. But right before the matches against Feyenoord, people would come up to me more often in the supermarket to say: 'You'll settle things this Sunday, right?' I could feel it was on people's minds; I could feel it in everything. That was very special."
On January 19, 2011, Ajax - Feyenoord was a one-time evening match. Ajax won 2-0. Alderweireld scored the 1-0 in that match. He describes it as his best Klassieker moment. "In that period, I often dribbled from the defense into the midfield but made the wrong choice many times. At that moment, I thought: I'm going to dribble and shoot. Looking back at it, I realised I was unsure what I needed to do. In the end, I scored a fantastic goal."
With Gaston Avila, Ajax signed an old acquaintance of Alderweireld. The duo played in Royal Antwerp's defense during the year they became champions. "Once Gaston joined our team, he grew a lot and showed an upward trend. I liked to play in the defense with him. With him, winning goes first, which is nice to have in the team besides his football qualities. His 'grinta', that is important."
"It's a great step for him and a wonderful transfer. Ajax now have a very young and good player added to their team. Someone with a South American temperament and an 'over my dead body' mentality once the whistle goes", Alderweireld continues. Did he have to convince the Argentine? "No", he laughs. "Ajax is on another level. If Ajax shows interest, it’s hard to say no. Ajax is such a big club that I have to convince very few people; that’s something the other Dutch people with us say, too."
Avila is one of the new players in the Ajax team. In the run-up to the Klassieker, Alderweireld, with his experience, knows what is important to bring the duel to a good end. "They have to keep their heads cool. In those days, we always had more quality than Feyenoord. Fighting the battle was important, but so was keeping your head in the game. Of course, it was intense, but our qualities always prevailed."
"With the fans their support, it can become an amazing match Sunday. If you win such a big match, it can be the start of something beautiful. You need a few turning points during the season which can decide the rest", Alderweireld concludes.