Winning duels with Tea is hilariously fun since she doesn't even consider herself a duelist lol
Seeing her win against characters like Pegasus, Keith, and Bakura feels satisfying somehow.
She actually dueled in the series and did very good, I'd say it's even funnier seeing Tristan schooling Marik, Bakura, Pegasus, etc. All of them end up shocked lol, Yami Yugi doesn't He respects every duelist
That isn't due to her being good, though. She forgot basic things in both her non-Joey duels. It's just that two of her opponents were terrible, and the other surrendered.
On-screen wins are a pretty bad indicator of how good a duelist is. Remember, characters like Mai, Bandit Keith, Rebecca, Rex, Weevil, Kaiba and Pegasus are or were all high-ranking professional duelists prior to the series.
Rebecca isn't a pro prior to her debut in the series. She was just a normal girl.
The others are indeed "pros", though. But as the above anon says, before Duelist Kingdom, duels are way too simple that being "pro" doesn't have much meaning.
I mean, Weevil literally won in like, two turns, just by arming Basic Insect with an equip to make it stronger than Rex's monster.
You're a good duelist if you grab your credit card, copy a very straightforward deck from DLM and win with that deck even if you have absolutely no idea, what you're doing. That's the definition of a good duelist.