Serena Williams has GOAT DNA on the court and apparently in her breast milk too ... 'cause the tennis legend says just a couple drops of her boob juice healed her painful sunburns!!
The 42-year-old -- who gave birth to her second daughter in August -- shared the unique remedy with her 1.6 million followers on TikTok ... just after she said an outing in the sun left her under-eye areas in a heap of pain.
Williams explained in a 46-second video that she had been told that putting breast milk on her kids' wounds could help speed up their healing processes .