Oosthuizen said the SA stripes helped him get his foot in the door to race a stint in Belgian club Baquet-Miba-Indulek-Derito for two and a half months in the middle of last year.
“The flag helped me to get into that club and race on a higher level,” Oosthuizen told In the Bunch.
“It was nice to stand out a little bit. Even though you have that team unit going on it was nice to be different within your team.
“Having that customised clothing, people sort of come to realise who you are. Looking different was quite special for me for the year.”
However the 19-year-old said while he was in Belgium the jersey did also place a target on his back.
“When you’re in a national jersey people know precisely who you are in the bunch. That affects aspects of racing as well.
“People tended to be more negative towards my racing. They sort of marked me, so I wasn’t really able to get into any breakaways or make any moves.
“It forces you to pick up your level. You still have to perform and if you don’t then others will use the excuse and count you lucky [for winning the national jersey].”
The Krugersdorp local said the added personal touch to his cycling attire, both locally and in Belgium, was the stand-out highlight for him.
“It is something I can put away in my cupboard then look at it in a few years and say I was a national champ and I raced that flag proudly.
“It’s also a special remembrance to have that little flag on my arm for the next three years as an under-23. It’s a goal you can set for yourself in the future again.”
Oosthuizen recently won the U23 men’s Gauteng champs ITT and spoke about how he had indirectly competed in that discipline against his father Thys, who took part in the veterans 40 years and older category.
“You can see how strong someone is in the time-trial,” he said. “You can measure where their form is at and physically how they compare to others.
“You know that you can ride this hard for that long and that’s purely up to you. So I’d like to get a podium. That would be nice.”
He added that the road race was usually a “gamble”. “So many things can happen. You can be on the wrong wheel at the wrong time and you can puncture or crash.
“Anything can happen. It’s really about rolling the dice.”
Oosthuizen said however that he would like to defend his title in the national road race, which “people don’t see often”.
“I’d like to make it through quite safe, race as hard as I can and be aggressive.
“In the race I’ll have to make decisions to make that outcome possible. But a podium in the road race would be quite satisfying.”
He stressed again that it would be a challenge going into the race as current champion, adding that the other riders tended to focus on the favourite and then “just don’t leave you alone”.
“If I happen to go into a breakaway with other elite riders it will almost immediately be closed down by the other U23 riders.
“You just have to assess at the racing on the day.”
The U23 and elite men will contest Sunday’s 162km road race simultaneously.