The top seed cruised through his quarter-final match 6-1, 7-5, 6-0 in one hour and 49 minutes on Court Philippe Chatrier, and is yet to drop a set at the French Open this year.
The 23-year-old will next face either 24-time Grand Slam winner Novak Djokovic or third seed Alexander Zverev for a place in Sunday's final.
"I just tried to stay focused on my side of the court, so I tried to stay as solid as possible because he (Bublik) can have ups and downs," said Sinner.
"It was a good performance from my side... against these kinds of players, you have to be very consistent.
"I'm very happy with how I've arrived in the semi-finals, semi-finals in Grand Slams are very special."
World number two Carlos Alcaraz said his last-eight dismantling of Tommy Paul on Tuesday was in part "inspired" by Sinner and his time-sensitive approach to tennis over the last fortnight.
Sinner has spent less than 10 hours on court through his first five matches as he has systematically taken apart his opponents for the loss of very few games.
"He (Sinner) inspired me in some ways just to give my 100 per cent every match, and I see how important it is just to play such a great level in the whole match, just to have more time then to recover after the match," Alcaraz told reporters after his 94-minute win.
And the Italian showed centre court just what his rival meant by wrapping up the first set in just over half an hour.
Bublik, ranked 62, managed to get a foothold in the second set as he matched Sinner game for game through the majority of the frame, but never managed to force a break point and really put pressure on the Italian.
Bublik then presented Sinner with his chance to secure a 2-0 lead with a double-fault when serving at 30-40 in the 11th game.
Not known for his propensity to look a gift horse in the mouth, Sinner closed out the second set by holding the next game to love.
He started the third by making it back-to-back breaks on Bublik's serve, before racing through the rest of the set and clinching the match at the first time of asking with a cross-court forehand.
Sinner now leads Bublik 4-1 in their match-ups, with his only defeat coming when he was forced to retire injured when trailing the 27-year-old at Halle two years ago.
"We've played a couple of times before, so I knew a little what to expect, but with him, you never know what's happening," added Sinner of his unconventional opponent.