The 22-year-old, who recently graduated from Newcastle University, proudly presented China's Xu Zhao with his gold medal for the 100m T46.
Wearing a stylish Peter Pilotto zip-front sail dress and black suede heels, the young royal waved to the crowd before warmly congratulating the athlete on his winning performance.
Earlier, Eugenie and her boyfriend, Jack Brooksbank, had enthusiastically cheered on competitors.
The couple, who have been together for two years after meeting on a skiing holiday, were seen in the crowd before duty called for the Princess.
Whilst the duo have previously kept a rather low-profile, they now seem to be more public about their relationship.
The Queen's granddaughter, who received a 2:1 in her English and history of art degree in July, has expressed her excitement about her future projects and official duties, including her charity work for the Royal National Orthopaedic Hospital.
"I'm a freshly finished student" she said, "so my future plans are coming together as we speak."
The Princess' solo engagement came on the eighth day of the Paralympics, which are due to finish on Sunday.
British band Coldplay have been spotted rehearsing in advance of their headline performance at the closing ceremony.
All the news as Duchess Kate's due date draws close...