Given the lack of definition I'd say it's difficult to tell.

How did you 'beat' them? Multiplayer race? Weapons on or weapons off? In the TT or SL record tables? (Eliminator?).

Was it a one-off? Was it multiple times on multiple tracks? What was the margin?

What's 'better'? Faster? More accurate with weapons? Better overall or on one track?

Even if you're just talking a straight up weapons off race then there is plenty that could have affected the other person's performance. Even if performance weren't affect at all, then it would still be hard to tell from only one race.

If you consistently beat someone many many times over a sustained period in various game modes, then possibly you can claim to be 'better'.

As Koleax says, having a ship with lower stats is redundant if you beat them. Ship choice is also relatively insignificant online. Even offline, in many cases, the stats increase is compensated by the fact that the ship handles oddly and is unfamiliar. Familiarity matters.

Now, if someone beat you by a narrow margin in, for example, Fury FEISAR on Sol 2 Phantom Time Trial, and you used HD FEISAR, then you could argue they had a stats advantage and that you're more even than the times on the board would suggest - even more so in the case of Harimau. But that's about it.

Anyway, don't worry about being better than anyone other than yourself. Just keep playing and keep improving.