The aim of this study was to characterise thoroughly the differences between Physics Olympiad competitors' and regular students' successes and approaches in relation to counterintuitive dynamics problems (CDPs) in order to discover some of the differences between skilled problem-solvers and those with fewer such skills. A total of 23 Physics Olympiad competitors were found by snowball sampling, while 40 regular students were selected by means of convenience sampling to participate in this study. To compare the students' solutions, we ran through six CDP of low, medium, and high difficulty. Students' responses were analysed by means of both qualitative and quantitative methods. The findings indicate that Olympians are much more successful and careful in handling CDP than regular students. On the other hand, regular students' challenges were often associated with a superficial problem-solving approach and with inadequate analysis of the problem. It can be concluded that, when compared to regular students, expert students' in-depth analysis resulted in greater successes and more efficient approaches in solving counterintuitive problems. Hence, it may be claimed that, with the use of counterintuitive problems, teaching and assessment practices may be developed to help students advance to higher hierarchical categories of problem-solving.