GM Kiril Georgiev is tied for 23rd place (out of 58) in the World Rapid Chess 2013. Perhaps his confidence took a beating when he was thoroughly demolished in his rapid game against the incredibly talented Bulgarian FM Borislav Ivanov.
"My game against Borislav Ivanov was played at ten minutes plus five second increment. He played very fast, which came as a big surprise to me. He spent between five and seven seconds per move, and never took more time on any of his moves during the game. For the whole game he was supporting his chin with his two hands. He was making his moves quickly and vigorously, displaying a high level of self-confidence at all times.
He nevertheless had a lot of time on the clock – at the end of the game he had over seven minutes left! He didn’t stand up even once during the game. Our game was not broadcast over the Internet. It made a strong impression on me that at some point, when the position was repeated twice, he thought for about three seconds and diverted, avoiding a three-fold repetition! Best Regards, Kiril."
One of the giveaways to me when I'm playing 10-minute games or more online that my opponent may be using an engine is when all his moves take almost exactly the same amount of time, regardless of their complexity; or even when the moves were part of a forced combination with only one legal move.
I'm not saying I'm '100%' positive Ivanov cheats, but I'm 99% sure.