Alex had last taken pole at the Argentine Grand Prix in April 2023 and he will be joined on the front row by Yamaha's Fabio Quartararo and Ducati's Marc Marquez, who leads younger brother Alex by 175 points in the championship.
"That was really special and really important to be in the front row today, especially because we had a really good pace during the weekend," said a beaming Alex, who has not had a podium finish in the last three rounds.
"Happy we put everything together but now comes the important moment -- the sprint race and the long race where the points are there on the table. So we need to be really concentrated."
Quartararo had set the lap record in Q1 to advance to Q2 along with VR46 Racing's Fabio Di Giannantonio, setting the benchmark in the shootout for pole position in the final qualifying session.
The record was first broken by KTM's Pedro Acosta -- in a lap that was later cancelled as the Spaniard had exceeded track limits.
In the shimmering late-summer heat, Alex then went even faster with a time of one minute 37.536 seconds as the Gresini garage erupted.
Marc attempted one last qualifying lap to try to snatch pole from his brother, but he nearly lost control before producing an incredible save to stay upright, deciding to abandon his attempt.
"That front row was the main target. I already understood yesterday and this morning that Alex had a bit more than us, especially in turn four," Marc said.
"He's super fast on the last two corners. But let's see, we start on the front row, it will be a big help for the race."
His Ducati teammate Francesco Bagnaia is third in the championship but a whopping 227 points behind, and any hopes the Italian had of competing in the sprint and race went up in smoke when he could manage only 21st fastest on the grid.
It was his worst qualifying performance in three years, and as heads hung low in the Ducati garage, Bagnaia could only look on in disbelief, hand on his helmet and elbow perched on the fuel tank, pondering how his season had slipped away.
