Sainz qualified fifth and team-mate Charles Leclerc seventh as the Ferraris struggled to get their tyres warmed up in a rainy end to Friday's sprint qualifying.
Leclerc went off when it started raining, bending his steering rack, which Sainz admitted could have easily happened to him too.
"With the intermediate tyres we waited a long time at the pitlane exit, they got cold, and then Charles and I struggled a lot on that outlap to warm up the tyres," Sainz explained. "I'm lucky I didn't suffer the same [spin].
"We couldn't do a good SQ3, but I think I saved the day with fifth. This is a very difficult track to get to and almost go straight into qualifying."
But with practice time limited on F1's return to Shanghai, Sainz said he couldn't get his SF24 set up to his liking in dry conditions either.
It has dampened his expectations for Saturday morning's sprint, which is expected to be dry, but on the positive side the new parc ferme rules allow teams to work on their cars again ahead of grand prix qualifying later on.
"The sprint race is in the morning, then parc ferme opens and we can change the car," he added. "I would like to be able to make a couple of adjustments to the car after the sprint race, because I don't feel comfortable.
"I have a couple of ideas to improve the car for qualifying. In the sprint we will have to survive with what we have and fight from fifth place."
Team principal Fred Vasseur hopes the team's tyre gambit in free practice will pay off in the sprint race.
"We were the only ones who left one more set of medium and hard tyres this morning," he explained to Sky Sports Italy.
"We have the advantage of still having a set of new medium tyres for tomorrow, while our rivals will have to use a set of used mediums. This means that we will have a wider choice in terms of tyres for tomorrow.
"But, like everyone else, we're a bit blind. It's not an easy choice, we only did a few laps this morning. We will have to choose the compound well tonight, because we have to consider that it can be a starting point for Sunday."
Explaining his off, Leclerc added: "It was very difficult to switch on the tyres, I tried to be a bit aggressive, but obviously I lost it out of Turn 8.
"That compromised a little bit our qualifying because then the steering was a little bit bent. But all in all, I don't think there was any miracles. There wasn't much more we could have done."
