The 27-year-old former Marumo Gallants and AmaZulu striker is currently leading the scoring charts with 12 goals from 22 Betway Premiership matches.
Rayners has 11 goals from 19 league games while Leon has netted five league goals from 10 games, that included five substitute appearances.
"I still [believe] he got to win the top-scorer [award], but he's got competition. He competes with lethal strikers because, in my opinion, his biggest competition is Rayners and Leon, he may have fewer goals, but he's scored far too many goals in a short space of time," Mngqithi said in the Sowetan.
"Then you say maybe in one match one day he will score four, and this thing [the Golden Boot race] is finished, but I have the belief that in the forthcoming games, with a little bit less pressure from the team, he [Dion] might be able to get more goals.
"I think he can do that if he can get a brace somewhere."
"I hope he achieves that because it'd be good for the club. I'm still looking at him at least getting four to five goals in our remaining game," added Mngqithi ahead of their upcoming clash with Orbit College at Olympia Park at the weekend.
Mamelodi Sundowns coach Miguel Cardoso has drawn a clear line between past and present ahead of the decisive semi-final clash in the CAF Champions League, urging his side to approach Saturday's encounter with renewed determination.
Esperance defender Mohamed Drager has offered measured praise of Mamelodi Sundowns ahead of their decisive CAF Champions League semi-final second leg, insisting the Brazilians are a major force but not beyond reach.
The 2025/26 Betway Premiership heats up this weekend with eight sides battling to make the top eight and others looking to avoid the relegation zone.
Keanu Cupido says Mamelodi Sundowns have the belief to go all the way in the CAF Champions League this season.
