Pouille, who demolished Spaniard Albert Ramos-Vinolas 6-3 6-2 yesterday, has put a new spin on the term "lucky loser".
The Frenchman lost in the final round of qualifying on Monday, and booked a ticket to Melbourne for the following day with his compatriot Stephane Robert, who had also exited at the last stage of qualifying.
But the 20-year-old decided to stay in Auckland and it has paid off in a big way.
"I wasn't supposed to play," said world No 136 Pouille.
"I was supposed to leave and I had my flight booked. [Then on Tuesday afternoon] I spoke to the tour manager and the other players and they told us there might be a chance to get in.
''I decided to stay, Stephane decided to leave, bad luck for him. He [has] been a little bit stupid maybe on this choice."
The ATP lucky loser system allows players who have been defeated in the final stages of qualifying - and are still on site - to come into the main draw, if there are any injuries or withdrawals.
When David Ferrer withdrew, Alejandro Falla replaced him as the highest ranked loser from the final round of qualifying. Robert (World No 133) was next in line, but he was in Melbourne by the time Tommy Robredo pulled the pin.
"It's a lucky loser and I am very lucky," said Pouille.
"During the morning Robredo told us he was not going to play. I knew I had a good opportunity and I took my chance 100 per cent."
It's an amazing situation but Pouille has justified his good fortune. He was superb against Michael Venus on Wednesday and was again clinical yesterday, against a player ranked more than 70 places higher. But we shouldn't have been surprised; Pouille is a young man on the rise, another classical player on the French production line.
He first grabbed the attention of the tennis world last October, where he went on a huge run in the Paris Masters.
Given a wildcard, Pouille beat Steve Johnson (world No 41), Jarkko Nieminen (69), Ivo Karlovic (27) and Fabio Fognini (20) in the space of four days, earning a quarter-final with Roger Federer. He lost 4-6, 4-6 but won high praise from the Swiss player.
"He has a beautiful technique, like all French players," said Federer.
"He knows how to do everything. He knows how to serve. He knows how to go to the net."
Pouille was obviously flattered; "It's always good to hear this from a player like Roger. It gave me a lot of confidence."
The 20-year-old could receive another massive shot in the arm today, if he can get past Adrian Mannarino, who dispatched Falla 6-3 6-1 in the first quarter-final.
The two Frenchman have been practising together and both are desperate to succeed; Mannarino is playing his first semifinal for almost four years while Pouille will break into the top 100 with more success in Auckland.
"We've been practising together the last three days but we won't [now]," said world No 44 Mannarino.
"We'll speak and stuff but we're not going to practise [or] warm up together."
In the third quarter-final Czech Jiri Vesely destroyed American Donald Young 6-2 6-3 in just over an hour.
The 21-year qualifier, who upset top seed Ernests Gulbis on Wednesday, was even more impressive yesterday.
The serving from the world No 63 was brutal and his power from the baseline extremely impressive at times, as he barely gave Young a chance.
