Although in recent years, cross-country short track (XCC) mountain biking became more popular among athletes and coaches, no study has analyzed the main determinants of performance in this modality. Thus, this study investigates performance and pacing profile of professional cross-country cyclists on different technical sections during a XCC competition. Twenty male professional cross-country cyclists (25.9 ± 5.4 years; eight under 23 and twelve elite), performed 6 laps of a XCC 2020 UCI International Mountain Bike Cup. Average speed (lap by lap and in five different technical sections of the track) were analyzed according to athletes, categories and race performance group. For race performance analyses, cyclists were divided into 4 groups (1-4; n=5 each), according to total race time, presenting group 1 the better performance. In general, XCC athletes adopted a positive pacing profile during competition but no differences in speed over the race or in each circuit section were found between categories (p > 0.05). Race performance groups adopted different pacing profiles: group 1 maintained a more even pacing profile, groups 2 and 3 adopted a positive pacing profile and group 4 adopted a reverse J-shaped pacing profile. No difference in speed was found between categories across track sections. Group 1 was 17.9% and 8.3% faster than the group 4 (p < 0.05) on the non-technical uphill section and more technical uphill/downhill section, respectively. A general positive pacing profile during XCC is adopted by the mainly of athletes and this choice of pacing profile is influenced by race performance, regardless of cyclist category. Furthermore, physical fitness is more relevant than technical ability in this competition.