Summary
The Saiyans are the most popular race of characters in theDragon Ballseries. While this mainly comes down to Goku, the main protagonist being a Saiyan, it’s also because the late Akira Toriyama, the series creator, has gone to great lengths to etch out the lore about Saiyans. They’re a powerful race of warriors who have an insatiable thirst for battle and have limitless combat potential. However, this doesn’t necessarily make them insurmountable or undefeatable.
Throughout theDragon Ballseries, there are quite a few characters who have defeated Saiyans. In fact, there are characters who have defeated multiple saiyans, including Goku, in combat. Thecharacters who have the most wins against Saiyansare either incredibly powerful, have access to impressive combat abilities and tactfulness, or both.

Piccolo may not be among the strongest characters now, but he does have two wins against Saiyans to his name. He’s no slouch either, because he was the strongest character among the Z fighters at multiple points during the events ofDragon BallandDragon Ball Z. The caveat is that both his wins against Saiyans came right at the beginning ofDragon Ball Z- in the same fight, in fact.
When Goku and Piccolo are fighting Goku’s brother Raditz, they run out of options and have to resort to Goku holding Raditz in a full nelson whilePiccolo fires a charged special beam cannonat the Saiyan brothers. The attack drills through both Raditz and Goku’s bodies, killing them both.

9Recoome
The Ginyu Force Warrior
Another unexpected character who has wins against two Saiyans is Recoome. Recoome is a member of the Ginyu Force, a powerful squad in Frieza’s army summoned to planet Namek to deal with the threat posed by Vegeta, Gohan, and Krillin and recover the Dragon Balls Vegeta stole.
DespiteVegeta’s multiple Zenkai boosts on Namek, the Saiyan prince is no match for Recoome, who comfortably tanks all of his attacks and handily defeats him. He’s about to finish Vegeta off until Krillin and Gohan rescue him and face Recoome themselves. Recoome comfortably defeats Krillin and then Gohan, his second Saiyan victim.

Broly made his debut in the filmDragon Ball Z: Broly - The Legendary Super Saiyan, in which he single-handedly defeated four Super Saiyans in the form of Goku, Gohan, Future Trunks, and Vegeta. However, Akira Toriyama has since retconned him into the canonicalDragon Balluniverse with the filmDragon Ball Super: Brolyin 2018.
In this film, he comfortably defeats Goku, Vegeta, and Golden Frieza before Goku and Vegeta perform a fusion dance and become Gogeta to finallydefeat the powerful Saiyan. So, while the non-canonical variant of Broly would have defeated more Saiyans, the canonical one only has victories against two Saiyans: Goku and Vegeta.

7Vegeta
The Only Saiyan to Defeat Goku
Vegeta was an absolute menace when he first made his appearance inDragon Ball Zduring the Saiyan saga. After he kills Nappa for failing him and losing to Goku, he battles Goku in a mountain range away from civilization. It is seemingly a stalemate, with Goku’s Kaioken technique evening the odds until Vegeta becomes the Great Ape.In this form, he cripples Gokuand later defeats Gohan, even in his Great Ape form.
He does get a couple of wins against Goku later in the series (one as Majin Vegeta, where Goku is holding back his Super Saiyan 3 transformation, and one in theDragon Ball SuperManga), but they’re against a Saiyan he has defeated before. So, Vegeta has defeated two Saiyans: Goku and Gohan.

6Cell
A Winning Streak Against Super Saiyans
Cell was a complete menace andthe main villain inDragon Ball Z’sCell Saga. In his semi-perfect form wherein he has absorbed Android 17 but is yet to absorb Android 18, Vegeta handily defeats him after training in the ROSAT with Future Trunks.
Vegeta allows him to absorb Android 18, believing it would be a better fight. In his perfect form, neither Vegeta nor Future Trunks are a match for him, and Goku goes on to lose against him in the Cell Games. This gives Cell victory over three Saiyans: Vegeta, Future Trunks, and Goku. Ultimately, he loses to Gohan.

5Android 18
Because Super Saiyans Aren’t Strong Enough
This might come as something of a surprise, butAndroid 18 has defeated more Saiyansthan Cell, Broly, or Vegeta. Vegeta, who is fresh from achieving his Super Saiyan form, challenges her to a fight. She defeats him by breaking both of his hands. Future Trunks intervenes, trying to save him, but he’s instantly defeated as well.
Just before the Buu saga, Android 18 participates in the Tournament of Power. She advances to the semi-finals where she faces an opponent called Mighty Mask, who is actually Trunks and Goten in a cloak. She defeats the two young Saiyans by exposing them as children participating in the adult category. So, Android 18 has victories against four Saiyans: Vegeta, Future Trunks, Goten and Kid Trunks.

4Buu
Defeated Every Saiyan Alive
Buu is the next big villain after Cell, and he ups the ante on the Saiyans as well. As Fat Buu, he initially faces Goku in his Super Saiyan 3 form. But Goku is only stalling here, so it isn’t a proper fight. He also defeats Vegeta, whose sacrifice as a Super Saiyan 2 is still not enough to defeat him. He later turns into Super Buu, and in this form, he defeats Gotenks, technically by absorbing him, and then defeats Gohan in his Ultimate Form. In his Kid Buu form, he goes on to defeat Vegeta again.
So, Buu has victoriesagainst every Saiyan except for Goku, giving him wins against four Saiyans: Vegeta, Gohan, Trunks and Goten. Needless to say, he’d have a victory against a Super Saiyan 3 Goku as well, had Goku not found Vegeta to fuse into Vegito, making Buu’s victories a lot more menacing.

Probably the second-strongest character discussed so far, Jiren is an opponent that the Z fighters face during the Tournament of Power arc inDragon Ball Super.He’s a member of the team from Universe 11 during the Tournament of Power and is considered a mortal who is even stronger than the God of Destruction in his universe.
During the Tournament of Power, he goes on to defeat Goku (multiple times), Vegeta, and Kefla (who is Kale and Caulifla fused with Potara Earrings). This gives him victories against four Saiyans, although two of them are from a different universe to Goku and Vegeta.

Simply put, Beerus isthe strongestDragon Ballcharacterwho has been discussed so far. As the God of Destruction of the Z Fighters' universe, he was all set to destroy the Earth but holds himself back, believing he would face the “Saiyan God” as a result. In an effort to find and fight said Saiyan God, he ends up defeating every Saiyan on Earth, as well as Goku in his Super Saiyan 3 form on King Kai’s planet.
This gives Beerus victories over Goku, Vegeta, Gohan, Goten, and Trunks in the filmDragon Ball Z: Battle of Gods.Beerus can comfortably go on defeating Saiyans for days on end.

1Frieza
By Genociding the Saiyan Race
It may be surprising to see Frieza here, because his presence indicates that he has defeated more Saiyans than even Beerus. But there’s a reason for this. In addition to defeating Vegeta and Gohan on Namek, he defeated Goku inDragon Ball Z: Resurrection F. He also defeats Cabba, the Saiyan warrior from Universe 6 inthe Tournament of Power Arc inDragon Ball Super.
He single-handedly wipes out the Saiyan race by destroying Planet Vegeta before the events of theDragon Ballseries. This gives Frieza the most wins against Saiyans across theDragon Ballseries.