Chijindu Ujah said he was hoping to fight his way to the top following his winning return at the European Athletics Championships, a year after serving his ban for a doping violation that resulted in his team being stripped of their Tokyo Olympics silver medals.
Sprinter Ujah took victory in his heat at Rome's Stadio Olimpico with a time of 10.23 seconds, which meant he qualified fourth-fastest for the men's 100m semifinals.
The 30-year-old was previously banned by the Athletics Integrity Unit (AIU) for 22 months in October 2022, which was backdated from August 2021 to June 2023.
However, the AIU had cleared Ujah of intentionally taking prohibited substances. He was recalled to Britain's 4x100m squad for the World Athletics Relays in May, but did not participate.
"We all make mistakes in life and obviously I made it at this level, which I didn't want to do. I know I can walk with my head held high, knowing I didn't try to cheat," Ujah told the BBC on Friday.
"I have learned a lot about myself, the resilience and the mental health, it has taken a lot to get back to this point... Hopefully I can fight my way back to the top."
Britain were stripped of the Tokyo silver after the Court of Arbitration for Sport upheld Ujah's anti-doping rule violation.