Fleetwood looked home and dry a few weeks ago with nearest rivals Sergio Garcia and Jon Rahm not going out of their way to catch him, but fellow Englishman Rose had other ideas.
The Olympic champion was a distant 10th on the money list before banking more than 2.4 million points with back-to-back victories in the WGC-HSBC Champions and Turkish Airlines Open to slash Fleetwood's lead to just 134,839.
The good news for Fleetwood is that Rose, after some thought on Sunday evening, has stuck with his planned schedule and will not contest this week's Nedbank Golf Challenge, meaning Fleetwood is guaranteed to increase his lead in a 72-man event which has no halfway cut.
And a third victory of the season in Sun City would give Fleetwood an unassailable lead in the battle to end the year as European number one, even if Rose triumphs in the season-ending DP World Tour Championship in Dubai.
"Hats off to Rosey for the way he's played the last couple of weeks," Fleetwood said.
"It's made it an interesting finish but I could make it a lot more boring this week if I have a good week.
"It's still kind of in my hands. I've got to keep concentrating on what I'm doing and I played nice last week. I went the last two rounds without a bogey but I didn't convert many of my birdie chances.
"I'd like to win the tournament and it's at that stage where every shot counts. I'd like to start tournaments off a little bit quicker. The last couple I have played okay on Thursdays and not scored very well and then you're behind the eight ball.
"I'd like to get off to a good start but if you don't, keep going and keep your head down.
"Aside from everything else that is going on, it's one of those tournaments that you'd love to win - I'd love to have my name on that path walking up the ninth hole (at the Gary Player Country Club)."
Fleetwood finished 14th in Sun City last year, improving in every round after an opening 75, and believes the course should suit his game.
"It's tough," the 26-year-old from Southport added. "You're not going to get away with shots off line this week. You really have to think about where you're putting the ball, even into the greens.
"I think with the wind swirling there's a lot of patience involved, a lot of knowing where you can hit and where you can't. It should in general suit me, but you've still got to play well, you've got to hit good golf shots, but I love the course."