Sega's Top Skater influenced Tony Hawk's Pro Skater during development.
Top Skater was a 1997 Sega arcade game built around a large skateboard-style controller and a racing-oriented downhill experience. Neversoft's developers played it during lunch breaks at a nearby bowling alley and studied how it presented skateboarding in an interactive environment. That hands-on exposure helped shape the early direction of Activision's project.
The influence was important, but the finished Tony Hawk game did not simply copy Top Skater. Neversoft believed Top Skater's linear racing structure lacked the freedom and fun they wanted, so the team shifted toward open-ended areas filled with ramps, rails, gaps, and objectives. Even so, the developers retained a racetrack-like feel in two of the original game's final levels.
This distinction explains why the answer is not Sega Rally, another Sega racing title, or a fighting and driving game such as Virtua Fighter or Crazy Taxi. Top Skater supplied a direct skateboarding reference point, while observations of real skaters and the X Games helped the team refine the game's tricks, movement, and presentation.