"My goal is a message of hope and courage" - Sebastien Haller

Haller was diagnosed with testicular cancer shortly after joining Dortmund from Ajax in July 2022. The 28-year-old striker underwent two surgeries and chemotherapy in the ensuing months, before getting the green light to link back up with his teammates on their return to training on 2 January 2023.

Watch: Sebastien Haller's road to recovery

After featuring in a winter friendly against Fortuna Düsseldorf and scoring a hat-trick against Basel, Haller made his competitive comeback on Bundesliga Matchday 16, playing 28 minutes of a 4-3 win over Augsburg. He assisted the winning goal for fellow substitute Gio Reyna in Mainz three days later, before making his first start in the Matchday 18 win away to Bayer Leverkusen.

The France-born Ivorian retained his place in the side for the visit of title rivals Freiburg on 4 February, known globally as World Cancer Day. He marked the occasion with Dortmund's third goal in a 5-1 win - his first in all competitions for the club - before pointing to the defiant 'F**k Cancer' slogan he has had sewn into his custom boots in celebration.

BVB also added a lump on the centre circle before the match, and during the half-time break, to raise awareness of testicular cancer.

"To score today was a great message to everyone who is fighting today or will fight later," Haller told bundesliga.com after his second successive 61-minute outing in the Bundesliga. "It gives some hope, some courage. That's it, you know? The days after will always be better.

"Since day one, I've had this in my mind to score in front of the Yellow Wall. To experience this atmosphere, this power. All the push they can give us, this boost. We need to use this as a boost for the team, for everyone. It was the best day possible.

"It's also my task to give everything for them [teammates and coaching staff]. They were here when I needed it. The only way to get points, to reach our goals is to stick together, to be as a team, to keep going like that for the rest of the season."

Watch: Sebastien Haller's first Bundesliga goal for Dortmund

Haller's goal helped Dortmund extend their winning run to four matches in 2023, whilst keeping pace with defending champions Bayern Munich in the six-way logjam for the title. Although the BVB No.9 now has 178 Bundesliga minutes under his belt since returning to competitive action, he admits to feeling the pace of top-flight football.

"It's still difficult [fitness], but it's only with minutes that I can be fully fit. Thanks to the staff and to everyone for helping me perform because of course it's not easy - my body's changed. There are a few things that are not the same, so I need to adapt every day to the new pain, the new everything. I just want to get the most minutes I can get and take it day by day.

"A lot of things are quite different, but the most important thing is to work well and work hard, but never go over the limit because I need some time again to recover from the second operation, that's normal. I can do everything, but I need time. This is what I'm training to do. It's a hard job, but it's nothing compared to the last few months. It's all been worth it to score this goal. I'm happy."

Watch: Haller - 'My goal is a message of hope and courage'

With the games coming thick and fast for Dortmund in the Bundesliga, DFB Cup and UEFA Champions League, Haller will have ample opportunity to build up his fitness to the point where he is able to complete the full 90 minutes. For now, head coach Edin Terzic is simply delighted to have his summer 2021 signing back healthy and in first-team contention.

"We were looking for this moment when we signed him in the summer," Terzic said of Haller's first Bundesliga goal for Dortmund. "We were hoping he'd score in his first game in the summer, but after what happened, all he's been through, it's a very special moment for him. And a very important goal for us - you can feel it. Hopefully he can continue like this."

Watch: Edin Terzic on Haller's 'special moment'

Given Haller's track record, more goals can be expected. Haller joined Dortmund after a record-breaking season with Ajax, during which he finished on an Eredivisie-leading 21 strikes. He also ended up third in the UEFA Champions League scoring charts behind Karim Benzema (15) and Robert Lewandowski (13) after scoring 11 times during Ajax's run to the round of 16.

Haller previously enjoyed a 33-goal spell in Germany with Eintracht Frankfurt (2017 to 2019), and has also played in France and England. He represented France up to U21 level, before declaring for the Cote d'Ivoire, for whom he's won 15 senior caps.