Daryll Neita could only claim silver after a narrow photo finish in the 200 metres at the European Athletic Championships in Rome on Tuesday.
The four-time British champion came into the competition with high hopes, competing in Italy where she lives and trains.
Despite initially thinking she had won, the 27-year-old was beaten by Switzerland's Mujinga Kambundji, being pipped by just 0.01s.
The sprinter remains Britain's second fastest woman ever and one of only three British women to ever break the 11-second barrier.
Neita went into the event hoping for her first European gold -- her previous best result in singles European competition was a bronze medal.
"I am honestly just so disappointed because I really wanted that medal," Neita said.
"I thought it was close on the line. I could feel myself dipping which isn't my strongest thing. I'm upset at myself because I came here for the gold. I know how much I should have got that."
Neita's silver was Great Britain's 11th medal of the competition.