Towards the end of Q1 Alpine driver Gasly was on a flying lap when he encountered a nearly stationary Sainz at the final chicane, as the Spaniard was creating space for himself to embark on a final lap attempt.
The incident forced Gasly off onto the escape road, which meant that the Frenchman stayed 17th and was eliminated, rather than improving his lap time to book a comfortable spot into Q2.
A furious Gasly responded that Sainz should be banned for it at the time and afterwards continued to say the Ferrari man's driving was "unacceptable".
Sainz's defence was that he was impeded himself by AlphaTauri's Yuki Tsunoda, who had overtaken him before the chicane and therefore forced the Ferrari man to start his flying lap later than planned.
After hearing from both drivers the FIA stewards have given Sainz a three-place grid drop for the grand prix, demoting him from eighth to 11th. It pushes Oscar Piastri up to eighth, Alex Albon into ninth and Sainz's team-mate Charles Leclerc into 10th.
In their verdict the stewards wrote the following:
"The Stewards heard from the driver of Car 55 (Carlos Sainz), the driver of Car 10 (Pierre Gasly), team representatives and reviewed positioning/marshalling system data, video, timing, and in-car video evidence.
"The driver of Car 55 stated that he was surprised that the driver of Car 22 overtook him into Turn 13 and as a result he accelerated late to start his fast lap.
"The driver of Car 10 stated that the driver of Car 55 could have and should have “gone earlier”. Telemetry showed a significant speed differential between Cars 55 and 10.
"Although the overtaking move by Car 22 took the driver of Car 55 by surprise, it is our determination that the driver of Car 55 was predominantly to blame and unnecessarily impeded Car 10."
"It was very tight with the flag, the flag was about to fall. I got impeded seven times today," Sainz said.
"I’m not shouting on the radio in Turn 13. Other drivers chose to use the radio more than others.
"Some incidents are under investigation others are not it depends how much you shout on the radio and how much you complain.
"The flag was about to fall and also it was a bit every man for himself and I had to go. If not I would have missed my qualifying lap also and I was getting impeded at the time too."
UPDATE: Later on Saturday evening Tsunoda and Aston Martin's Lance Stroll were also put back three places for impeding offences in the same session.
Tsunoda went off the road in Turn 10 and instead of backing out of his flying lap, he returned to the racing line and hindered Haas' Nico Hulkenberg, who was also on a flyer behind him.
Stroll drew the ire of Esteban Ocon after impeding the Alpine driver into Turn 8, which will also cost the Canadian a three-place grid drop for his home race.
Tsunoda was demoted from 16th to 19th, while Stroll dropped from 14th to 17th.
