Team GB sprint cyclist Victoria Pendleton was initially denied access into the BMX track to watch her compatriots Shanaze Reade and Liam Phillips contest for a place in the final.
The 31-year-old won silver in the women's sprint event on Tuesday after being demoted to second in the first of three races after coming out of her lane just as the heat began.
Pendleton tweeted: "Have just been denied access to the BMX, as the security changed the rules, what's with all my bad karma recently!"
Despite the initial snub, minutes later Pendleton, who has now retired from sprint cycling, was allowed in to cheer on her fellow Team GB athletes.
She added on Twitter: "Am at the BMX, it's turned out to be a beautiful day! Go@liamPHILLIPS65 and @ShanazeReade we are all behind you."
The British cyclist also won a gold medal in the women's keirin event earlier this week.