The 24-year-old improved by 17 places in four years since London
Arthur Lanigan-O'Keeffe has finished in 8th place in the men's Modern Pentathlon at the Olympic Games.
The reigning European Champion began in the day in 25th place after earning 196 points in Thursday's fencing event. The Kilkenny native won 16 of his 35 matches in the opening round.
Lanigan-O'Keefe began Saturday's events in the swimming pool, where he finished fourth in the 200-metres freestlyle. A time of 2:03:03 moved him up to 13th place overall after all the swimming heats had been completed.
Despite a disappointing performance on Thursday, Lanigan-O'Keeffe returned to the piste for the fencing bonus round where he picked up two important points to bring his total to 529. The Kilkenny was lying in 26th place overall with his two victories in fencing over Andriy Fedechko and Adam Marosi before being defeated by Jinhwa Jung.
The 24-year-old jumped a clear round in the showjumping competition, which gave him the maximum 300 points. His result lifted him into 15th place overall on 829 points.
Starting in 15th place overall and 42 seconds behind the leader and eventual gold medal winner Alexander Lesun from Russia in the combined cross country and shooting event, the Kilkenny man finished in 8th with 1457 points.
After a 25th place finish in London, his top ten finish in Brazil marks a huge improvement over the course of four years.
Lanigan-O'Keeffe's performance follows Natalya Coyle's seventh place finish in the women's competition on Friday night.