The Diamond League arrived in Europe for the first time this season on Thursday night with Gemili making sure to leave his mark in the 100m in a time of 10.07seconds.
Just shy of his 10.05 personal best, he finished third behind winner Justin Gatlin, who clocked 9.91, and Jamaica's Nesta Carter (10.02), while Britain's world indoor 60m champion Richard Kilty came home in ninth.
"It's a great feeling to come third in a field like that. I love racing; it's what we train every day for, so to do it on a stage like that with an awesome crowd, it's great," said Gemili, who improved on his time of 10.08 seconds from last weekend's Bedford International Games Open.
"It was better than last week and the times are getting quicker, so as long as I keep getting better and keep working hard I can't see why I can't keep it progressing, and hopefully I can glue that together with a good second half and the times should be quicker."
Earlier in the evening Child shaved almost a second off her season's best, clocking a time of 54.82 in the 400m hurdles for third behind Kaliese Spencer of Jamaica and America's Georganne Moline.
She said: "I'm delighted with that even though the race didn't go quite as planned. We've been trying a new stride pattern in training, which I lost a little bit at hurdle five but it was a solid performance and it was great to be in amongst it. Hopefully I can just keep shaving a bit off my time every race.
"I was thinking if I could run low 55 seconds I'd be happy, so to go sub-55 I'm really happy. There aren't many girls who have gone under 55 seconds yet this year, so it's a nice place to be."
Elsewhere, Tiffany Porter finished fifth in the 100m hurdles while Jo Pavey clocked a season's best of 15:04.87minutes in the 5000m to finish tenth ahead of Julia Bleasdale in 14th.
Nigel Levine also recorded a season's best on the way to seventh in the 400m, one place ahead of Conrad Williams, and Brett Morse finished 11th in the discus with a throw of 58.88m.
- Sports & Recreation
- Justin Gatlin
- Nesta Carter
- Richard Kilty