Goku wasn't just a Super Saiyan, he was an ascended Super Saiyan.
Vegeta was just a powerful Super Saiyan well on his way to ascended Super Saiyan. Trunks went for Ultra Super Saiyan.
Ascended is just...the level between 1 and 2. It's getting extremely close to 2 by having high power and retaining high speed, without fully hitting 2. They were probably physically weaker than USSJ Trunks, but were still close to his power while STILL having speed to fight back.