There is a lot of competition in the world of sports, with many athletes wanting to be the fastest or the best. Often there is a lot of pride involved, as well. Sometimes, an athlete thinks he or she is the best in a certain field, until someone better comes along to challenge them. In this idiom, we have the image of a runner going fairly quickly, and then another runner not only catching the first one but actually going so fast that runner #2 is able to take the time to run in a circle around runner #1 before proceeding to run ahead and win. The second runner's action is a kind of insult aimed at the first runner. From this image, we are able to use this idiom in any situation where a second person, team, corporation or group is able to outperform the best efforts of some other person, team, corporation or group.