The two Ferrari drivers were embroiled in a four-way fight with Fernando Alonso and Sergio Perez for third place in the second half of a thrilling 19-lap encounter in Shanghai.
Alonso sat third, with Sainz in his wheel tracks, hotly pursued by Perez and then Leclerc.
Poor traction for Alonso out of Turn 6 with four laps to go saw the battle heat up, with Sainz drawing along the Aston Martin through the sweeping Turn 7/8 complex.
Wheel-to-wheel, the pair touched and eventually opened the door for Perez to storm through on both of them at Turn 9.
Both Alonso and Sainz picked up damage in the clash, forcing the Aston Martin driver into the pits and retirement.
Sainz was able to continue, though he soon came under attack from Leclerc.
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“I did a good start; I was pushing Max [Verstappen] hard at the beginning because I knew if I was passing him, I had a strong chance of winning the race,” he explained to Sky Sports.
“That probably killed my tyres a bit and then I was managing for the rest of the race until I got Fernando.
“Behind Fernando, I think I did a really good move around the outside of Turn 7. I think from then on, he decided to be a bit of all-or-nothing into me into Turn 9, which cost us both the race.
“I picked up damage and a lot of dirt in my tyres from the optimistic move.
“From there on, I was sliding around with damage in the car and dirt on my tures, and I was doing everything I could to defend and obviously sliding.
“Maybe had a moment there with Charles, but I apologise if I did something over the limit, but we were all racing really hard today.
“I was trying my best to keep it under control.”
On Lap 17, Sainz and Leclerc clashed at the Turn 14 hairpin when the former went defensive after this team-mate used DRS to pull alongside.
With the inside line, Sainz held Leclerc wide, forcing him off the road as he struggled to hold on to fourth place.
It was to no aveil as he lost the place and quickly fell back into the clutches of Lando Norris behind.
Speaking after the Sprint, Leclerc described the move as “over the limit.”
“To be honest, I have crossed the line also myself in the past, and when this happens we normally have a discussion, we clear the air, which we went through that in the past already, and it went really well,” he told Sky Sports.
“So I have no worries that it won’t be the case also this weekend also, but today he went a bit over the limit.
“Contact between us two, being in a different race situation because I had saved quite a bit the tyres, I had a good pace at the end.
“It’s a bit of a shame that we lost that gap to Perez and couldn’t go and take him, but it’s like this.”
The moment between the two Ferrari drivers caught the eye of the stewards who noted it, but deemed there was no further investigation necessary.
Stewards didn’t hold the same view on the Sainz-Alonso battle, summoning both drivers over their clash.
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