Justin Gatlin says he means business when he lines up in the 100m sprint at the Diamond League meeting at the Stade de France here on Friday. The 2004 Olympic sprint champion, speaking Thursday on the eve of this key London 2012 Olympic Games trial, told a press conference: \"Races like this definitely keep you sharp. \"It gives me a chance to see how my competitors are doing, and they get a test of what I\'m doing as well going into the Olympics.\" Gatlin, coming back from a doping ban, and fellow US sprint heavyweight Tyson Gay, turn up in Paris having both qualified for the US team for the July 27-August 12 Games, coming through unscathed from their notoriously tough national trials in Eugene last week. A relaxed Gatlin added: \"I feel good, I\'m coming here focussed, I\'ve got this race to worry about, then I\'m back home to prepare for Monaco and getting prepared for London.\" Assessing Friday\'s race which also features France\'s double European champion Christophe Lemaitre Gatlin commented: \"It\'s going to be good competition, a preview going into the Olympics, there\'s a stellar field. \"I want to be in good shape going into London, I want to run a good time here before going into my Olympic training camps.\" Detailing what he is hoping to take from Friday\'s race he said: \"I want to have a good start and focus on the end of race and keeping it strong at the end.\"