I'd go by the flight aura argument, considering Toriyama was surprisingly consistent with it necessitating a certain threshold of Ki. Before the cries of "B-but Videl broke Spopovich's neck!" Spopovich was noted to need to put in barely any power to his Ki blast as to not accidentally kill Videl, showing he was suppressing his Ki, not to mention we clearly see Videl lacks any aura whereas Spopovich and Yamu's are on full display. Whilst I'm unsure of the accuracy to the Japanese manga, the anime even refers to it as a Kiai-ho; a small Ki blast only slightly greater than a kiai in intensity.
All that said, I'd argue Spopovich is indeed above the likes of Raditz, so he solos as long as hax such as the Akkumite beam and Mafuba are banned, or as long as he's aware of his opponents' abilities and is going for the kill.