Brussels -Justin Gatlin has warned that he will be "hungry" when the Rio Olympics roll around in 2016 after bringing to an end a "successful yet bittersweet" year in which he won double world sprint silvers.
Gatlin, in the absence of Jamaican star Usain Bolt, won the 100m in 9.98sec at Friday's season-ending Diamond League meet in Brussels, but sustained a thigh strain that saw him withdraw from the 200m as a precaution.
The controversial American, who has served two doping bans, said his experience at last month's world championships in Beijing had been "bittersweet", as Bolt beat him into silver in both the 100 and 200m.
"I regard it as a successful season," the 33-year-old said of 2015, when he set the fastest 100m of the year back, 9.74sec, in Doha in May.
"I've been leading from the start of the season so for me to come out here and do something is successful within itself.
"To be able to come away from a world championships and win medals where there were some athletes who are great athletes who didn't even get to the finals or make the podium in Beijing, so to come away with two silvers, I'm happy with that.
"Obviously I want more so that's going to make me hungry in 2016."
Looking back at his Beijing experience, Gatlin said: "It's bittersweet. Obviously I wanted to go out there and win and run a very fast time.
"In track and field, sometimes you run fast and sometimes you surprise yourself and the audience when you do run fast, that's for any track athlete.
"To be able to come away with two silver medals is still very, very good."