Verstappen produced a stunning time of one minute 09.623secs to the delight of the packed grandstands, finishing over half-a-second quicker than Mercedes' Valtteri Bottas, with Lewis Hamilton third quickest, almost eight-tenths of a second down.
For the fourth time across the three sessions, though, the red flags were brought out as Sainz lost the rear of his SF21 on the approach to the banking into turn three.
Emerging out of the second corner, Sainz appeared to be carrying too much speed, which threw him out of kilter across the camber change into the left-hand banking.
Braking heavily, and turning through 180 degrees, Sainz instantly hit a barrier with the left front of his car, the impact spinning him around and leading to the rear of the car also smacking hard into the barrier.
Sainz claimed to be at a loss as to what had occurred, albeit leaving Ferrari in a race to get his car ready for qualifying, and potentially facing a five-place grid penalty for a gearbox change.
Following a 12-minute delay, and with Verstappen yet to take to the track 31 minutes into the hour-long run, the Dutch driver's first flying lap on the medium compound saw him move to the top of the timesheet with a one minute 11.225secs.
Verstappen's advantage was short-lived, though, as Bottas usurped him by 0.008s, albeit on the soft-compound tyre.
Continuing on the mediums, Verstappen then set the best time of the weekend with a 1:10.702s, but as the times tumbled, Alonso shaved 0.032s off that on the softs.
Bottas then returned to the head of affairs almost half-a-second ahead of Alonso, only for Verstappen to blitz the circuit on his soft-tyre run by setting a 1:09.623s.
Verstappen was aided in the final sector by a tow from team-mate Sergio Perez. That led to a chuckle over the radio from the F1 title challenger who said: "Hey guys, last sector doesn't get any better than that thanks to the tow."
Red Bull's Sergio Perez, following a tricky Friday for the Mexican, was the only other driver within a second of Verstappen, finishing 0.903s adrift.
GPFans is a multi-platform, multi-language brand dedicated to Formula One coverage. We bring you all the ins and outs of the sport, 24/7, everything from up-to-the-minute news and features to the latest viral stories and clips.
We believe that a new generation of exciting, outspoken drivers will make F1 more popular than ever before, and we want to give our users access to as much of their heroes as possible, on and off the track. From Lewis Hamilton to Max Verstappen, Daniel Ricciardo to Sebastian Vettel, we provide in-depth analysis of every every Grand Prix in the season, from Australia to Abu Dhabi.
With Formula One under the new ownership of Liberty Media, how the sport is being covered is evolving, and GPFans will look to be at the heart of this progression into new media, as one of the fastest-growing sites covering the king of motorsports.