Zhongli was fighting desperately. Just who is he? Zhongli thought to himself. No normal human could hold their own this good against a god. He kept summoning pillars because, without revealing himself, he stood no chance. Eventually he decided to summon a 500 foot pillar under Childe, launching him into the sky. Zhongli noticed Tartaglia's eyes gain a sudden sparkle when the rock impacted him. He watched Childe fly limply into the sky.
An hour later, Zhongli saw Childe come crashing to the ground. He rushed to catch him before he got even more hurt. He dived before Childe hit the ground and the sudden impact knocked the breath out of him. He wiggled up into a sitting position, Tartaglia's head resting in his lap. He couldn't see the man breathing. He panicked a bit and checked Childe's pulse. He was still alive. But barely.
He picked the man up, bridal style, and had a flashback to when he first met the guy. He was holding him like this. Childe reminded Zhongli of someone he used to know.