The Monegasque, who is competing as a wildcard in Paris, defeated world No 31 Cameron Norrie 7-6(4), 6-4 in the third round at the Paris La Defense Arena.
The big-serving Vacherot saved all five of the break points he faced in the match and broke the 30-year-old Brit for the only time in the fifth game of the second set.
Vacherot’s win against Norrie was his third victory at the Paris Masters after he saw off Jiri Lehecka and Arthur Rinderknech in the opening two rounds.
Remarkably, Vacherot has now won 10 successive main draw matches at Masters 1000 level as his Paris run has followed his staggering surge to the Shanghai Masters title earlier this month.
Vacherot is only the second ever player to win 10 or more consecutive matches at Masters events while ranked outside the top 20 after David Nalbandian in 2007.
In Shanghai, Vacherot shocked the tennis world by securing his maiden title as a 204th-ranked qualifier, winning nine matches (seven in the main draw after two qualifiers).
His victory at the ATP 1000 tournament in China saw his ranking skyrocket 164 places to world No. 40. His previous career-high ranking was 110th.
With his three wins en route to the last eight in Paris, Vacherot has collected 200 points, which has boosted his tally to 1,483.
This has moved Vacherot from 40th to a projected new career-best position of 30th in the Live ATP Rankings.
If Vacherot advances to the semi-finals, he will move to 1,683 points, which would put him 24th in the rankings.
Losing in the Paris Masters final would see Vacherot jump to 1,933 points, leaving him 23rd.
If Vacherot were to secure his second straight Masters title, he would have 2,283 points, which would put him 19th in the current live rankings.
What did Vacherot say about his ranking rise after beating Norrie?
After his win against Norrie in Paris, Vacherot explained how he was derailed by an injury last year when at his previous career-high ranking of 110th.
“Before I actually sustained an injury, I was ranked 110. There were a lot of points to defend, so I went down in the ranking,” he said in his press conference.
“But what is crazy is that I played much better this year rather than last year, and it was so hard for me to reach the quarter-finals.
“I didn’t reach a lot of semi-finals and finals, but I continue to believe in it right now. Maybe what was abnormal, it was rather to be ranked No. 204. I knew that I could play better. I didn’t really think about it.
“I knew that my level was closer to the top 100, and then that I could break into the top 50 rather than being actually ranked 200.”
Vacherot will take on world No. 10 Felix Auger-Aliassime in the quarter-finals of the Paris Masters on Friday.