Wallace Spearmon wins the 150m in Manchester in 14.87 (Getty Images) © Copyright
In their first ventures of racing on the purpose built straight line track in Deansgate which bisects the north of England city centre, the pair stormed to convincing 150 metres and 200m successes with impressive times.
Spearmon, disqualified after placing third at the 2008 Beijing Games, showed he is in shape to atone for that huge disappointment later this summer when powering to a time of 14.87 seconds well clear of Dwain Chambers and Marlon Devonish.
The 27-year-old, who missed most of last summer's track season with a strained left Achilles but has been in sparkling form since his return this year, easily held off the Britons' challenges with the duo finishing in 15.27 and and 15.37.
Richards-Ross, another who has underwent her fair share of career setbacks particularly in 2010 with a very serious quadriceps injury, took to the street concept as though it was the most natural way of running a 200m race.
This year's IAAF World Indoor 400m champion passed 100m in 11.63 then 150m in 17.01 - which would have given her victory in the official race which fellow American LaShaunte Moore won in 17.05 - before rounding off her never ending dash down the track in a time of 22.71.
That saw her easily despatch European Indoor 400m champion Denisa Rosolova of the Czech Republic to second place in 23.53 with Margaret Adeoye of Great Britain third clocking 23.56.
"I just loved the whole race and running so close to the spectators was amazing," said Richards-Ross the world's most prolific 400m performer, her eyes this summer set on winning the Olympic crown. "I like the whole idea and would love to come back again. It was a phenomenal experience."
European and Commonwealth 110m Hurdles gold medallist Andy Turner missed out on winning a third consecutive Manchester win with former World champion Ryan Brathwaite taking the honours in 13.60 from the USA's Olympic silver medallist David Payne (13.67) and three-time German champion Matthias Bohler (13.85).
Turner later returned to the track to win the 200m hurdles in 22.54 ahead of 2004 Olympic 400m hurdles gold medallist Felix Sanchez from the Dominican Republic who clocked 22.75 with Trindad & Tobago's World Junior 400m Hurdles champion Jehue Gordon third in 23.00.
The other track events saw Moore, before her 150m success, win the 100m in 11.41 from Germany's European champion Verena Sailer (11.54). Christian Malcolm took the men's title from Frenchman Jimmy Vicaut by 0.01sec in 10.46, while Norway's Jaysuma Ndure claimed the 200 in 21.27.
Unfortunately a speedy 100m hurdles victory for the host nation's Jessica Ennis ahead of top American's Dawn Harper and Danielle Carruthers was declared null and void after it was discovered because of human error, there were only nine sets of hurdles rather than the required ten put out on the track for the race.
"On behalf of all those staging the Great CityGames today, we would like to apologise for this unacceptable incident, and in particular to the athletes," organisers said in a statement.
Just a few blocks away from the the track venue and in front of a packed crowd in Albert Square, German Lisa Ryzih won the Pole Vault clearing 4.50m ahead of the World Indoor bronze medallist and local girl Holly Bleasdale who produced a best height of 4.43m.
David Martin for the IAAF
Powerade Great CityGames Manchester
Leading Results -
100m: 1, C Malcolm (GBR) 10.46, 2, J Vicaut (France) 10.47, 3, M Lewis-Francis (GBR) 10.49, 4, P Hession (IRL) 10.75
150m:1, W Spearmon (USA) 14.87, 2, D Chambers (GBR) 15.27, 3, M Devonish (GBR) 15.37, 4, F Obikwelu (POR) 15.70
200m: 1,J Ndure (NOR) 21.27, 2, J Ellington (GBR) 21.30, 3, D Neville (USA) 21.34, 4, L Lennon-Ford (GBR) 21.62
110m hurdles: 1, R Brathwaite (BAR) 13.60, 2, D Payne (USA) 13.67, 3, M Buhler (GER) 13.85, 4, A Turner (GBR) 14.16
200m hurdles: 1, A Turner (GBR) 22.54, 2, F Sanchez (DOM) 22.75, 3, J Gordon (TRI) 23.00, 4, R Yates (GBR) 23.23
100: 1, L Moore (USA) 11.41, 2, V Sailer (GER) 11.54, 3, C McGrone (USA) 11.57, 4, J Maduaka (GBR) 11.68
150: 1, L Moore (USA) 17.05, 2, M Douglas (GBR) 17.73, 3, S Tavares () 17.82, 4,D O'Rourke (IRL) 18.25
200: 1, S Richards-Ross (USA) 22.71, 2, D Rosalova (CZE) 22.53, 3, M Adeoye (GBR) 23.56, 4, N Sanders (GBR) 23.79
100m hurdles (One hurdle short): 1, J Ennis (GBR) 12.75, 2, D Harper (USA) 12.86, 3, D Carruthers (USA) 13.02, 4, G Bennett (GBR) 13.54
Pole Vault: L Ryzih (GER) 4.50, 2, H Bleasdale (GBR) 4.43, 3, N Buchler (SUI) 4.26, 4eq: A. Kolasa (POL)/K Byres (GBR) 4.16