Both drivers made pointed remarks over the radio during Q1 on Saturday as they tussled for track position while running in third and fourth respectively.
Leclerc said "nice, Carlos, nice, good overtake in the last corner..." after Sainz passed him on track for position, despite the Monegasque driver having priority in the session.
Sainz then said: "It's a bit unfair what you're asking me to do there. Sacrifice my tyre temperature. But anyway, whatever. Also, I am P4, he is P3, I am more at risk."
Speaking after the session, both drivers said they had overreacted, with Leclerc blaming adrenaline while Sainz said it was a "high pressure, high tension moment" and said he was at risk of not getting a lap in.
Asked by Autosport what the thinking was behind the pair swapping places, Leclerc said: "In the pitlane, it's something that we were expecting as we are always trying to get out the cars at the same time as it's better to manage the cars coming.
"But then on track obviously this is where we had a bit more of a discussion. We have one race where I have the priority to choose whether I want to be in front or behind, and one race Carlos has the priority to choose whether he wants to be in front or behind.
"I had the choice here and I decided to be in front, then at the end, we were very tight on timing and I think it was very difficult for us to know whether we were going to get past or not before the flag and Carlos decided to overtake.
"It is not ideal, we will discuss it. It had no influence, so no big deal.
"Obviously with the adrenaline inside the car and you don't know at that point if you're going to make it, the radio message was probably a bit more aggressive than it should have been."
Source: Autosport