Usain Bolt accused sprint rival Justin Gatlin of "disrespect" after proving his fitness for the Rio Olympics in emphatic fashion at the Muller Anniversary Games on Friday night.
The six-time Olympic champion, making his first appearance since pulling out of the Jamaican trials with a hamstring strain, clocked 19.89 seconds to win over 200 metres, his first race over the distance this season.
He led coming off the bend, but appeared to have to work harder than usual down the home straight.
The 29-year-old received a medical exemption to miss his trials, with two-time drug cheat Gatlin, his main rival for 100m gold in Rio, one of a number of United States sprinters who claimed he got preferential treatment he would not receive were he American.
"He's injured, gets a medical pass, that's what his country does. Our country doesn't do that," Gatlin was quoted as saying in the American press.
Bolt, who was hailed as the saviour of his sport after his 100m and 200m victories ahead of Gatlin at last year's World Championships in Beijing, hit back by saying: "For me I felt it was a joke - I felt it was a disrespect they think I'd back out of a trials.
"I've proven myself year on year that I'm the greatest. I laughed when I heard it; I was disappointed, especially in Justin Gatlin."
Bolt, back at the Olympic Stadium where he won three golds at London 2012 and in his final race before Rio, was greeted with the customary roar of approval when introduced to the crowd and responded with his famous 'Lighting Bolt' signature pose.
Fans are accustomed to seeing Bolt fly clear of the field in the home straight in his favoured event, but there was little sign of that here, suggesting there is still some way to go before he can live up to his extravagant pre-event boast that he could challenge his 200m world record of 19.19secs, set back in 2009, in Rio.
It was also down on American LaShawn Merritt's world-leading time of 19.74s, with Gatlin just one hundredth of a second behind.
He declared on the eve of the race that he was fully fit following treatment from his German doctor Hans-Wilhelm Muller-Wohlfahrt, but this was still a crucial fitness test ahead of the Games and his bid for an historic 'triple triple' of 100m, 200m and sprint relay crowns.
Bolt said it was one he had "definitely" passed - and, running into a slight headwind, he was right, even though he admitted to feeling rusty due to his lack of races.
Briton Adam Gemili, one of those closing on a grimacing Bolt as the line approached, clocked a season's best 20.07secs to finish third.
"The execution wasn't perfect, but it was my first run so I can't complain," the Jamaican said.
"My preparation definitely feels on track. I feel I'm in better shape than I was last year.
The best British performance of the night came from Laura Muir, who broke Kelly Holmes' national 1500m record with a hugely impressive run.
The Scot powered well clear of the field to come home in 3:57.49, winning by more than three seconds and eclipsing double Olympic champion Holmes' mark of 3:57.90 from the Athens Olympics in 2004.
The time ranks her second in the world this year, making her a real medal contender in Rio.
The 23-year-old said: "I'm over the moon with that. It's not just any record: it's Kelly Holmes' Olympic gold medal record. It's great to have.
"I was confident already going into Rio, but to take a Diamond League record on home soil going into the Olympics, that couldn't have made my confidence any higher."
The newly-laid track at the Olympic Stadium was clearly super-quick and, in near-perfect conditions, Great Britain's women's 4x100m relay team also made a significant statement of intent ahead of the Olympics by setting a new national record and the fastest time in the world this year.
The quartet of Asha Philip, Desiree Henry, Dina Asher-Smith and Daryll Neita claimed a dominant victory in 41.81, taking 0.29 off the previous British record.
Christine Ohuruogu emphatically justified her inclusion in the British team for the individual 400m in Rio by running the fastest time in the country this year at 51.05, although it was only good enough for fifth.
Eilidh Doyle, fresh from a Diamond League win and personal best of 54.09 in the 400m hurdles in Monaco a week ago, was made to pay for a bad stutter going into the final barrier as she had to settle for fourth place in 54.70.