His time in Thursday's Diamond League race did not match that Irish national record from Rio of 47.97 but was 0.44 faster than his season's best time.
In a freakish women's 200m, Dutch world champion Dafne Schippers was reinstated as victor having initially been disqualified after finishing first.
McCartney is preparing for the world championships in London in August., and will continue her build-up at Diamond League events in Stockholm and London.
Olympic bronze medallist Eliza McCartney has failed to clear her first height at the Diamond League meet in Oslo.
In a controversial 200m race, Dafne Schippers was eventually handed the win.
The Dutchwoman won comfortably in 22.31 seconds before her disqualification was announced and Ivorian Murielle Ahoure, who finished in 22.74, was handed the win.
"It was noisy at the start, so much noise, very hard to concentrate", she said.More news: Meghalaya woman guest in Khasi dress told to leave Golf Club
No further explanation was given.
Canada's triple medallist from Rio, André De Grasse, won the men's 100m in 10.01sec to defeat Britain's Chinjidu Ujah (10.02), the victor in Rome last week, and Ben Youssef Meité of Ivory Coast (10.03).
"I could have run faster today but it doesn't matter because it was a insane experience", said the Norwegian star.
Semenya wasn't the only South African in action as 400m hurdler LJ van Zyl ended seventh in 49.89, as local hero Karsten Warholm set a new Norwegian record of 48.25 as he was cheered on by the home crowd. I wanted to start in December, but I had a small injury to contend with. "But I hope all will be better in coming weeks, otherwise I felt good".
Wightman beat Kenya's Elijah Manangoi into second place, finishing in a time of 3:34.17 to smash his previous Personal Best by over a second.
Olympic champion Caster Semenya snatched a win in the women's 800 metres as she passed Francine Niyonsaba on the final straight after the Burundian runner led at the bell.