Sainz’s car was badly damaged when he ran over a water valve cover that had popped up early in the first session at the new venue, while Esteban Ocon also ran over it and suffered serious floor and chassis damage.
Both drivers had to switch to spare chassis for FP2, while Sainz picked up a 10-place grid penalty for taking an extra energy store and internal combustion engine.
Stella said that the incident was a reminder that track safety is paramount.
"Anytime you have an issue with manhole covers, it's very disruptive,” he told Autosport. “Like you saw with Williams in Baku [for George Russell in 2019].
"I think Jenson [Button] hit a manhole cover in Monaco [in 2016], it just destroyed the front wing immediately. And in that case, it was a low speed, because it was out of corner one in Monaco.
“So I think after this episode, there will be a raised level of awareness as to the fact that the standards associated with this potential risk need to be just higher. And essentially, it needs to be absolutely failsafe."
Stella admitted that he was relieved that the FIA was eventually able to run FP2 given the need to check the track thoroughly.
"On new tracks and street circuits we have seen before that these kinds of issues can happen,” he said. “In fairness, when I saw that type of issue, I was a little worried that a solution could have been difficult.
“So I would like to praise the fact that actually there was a good response from all the technicians, engineers, and the FIA as well.
"We got a session, and it was good that all the parties understood that we needed to be flexible with the tyre return, for instance, with the duration of the session.
“It's just a shame that the spectators haven't seen cars on track yet, because they needed to go.”
McLaren finished the extended FP2 session with Lando Norris in 11th, and Oscar Piastri three places behind.
Stella admitted that it hadn’t been an easy session for the Woking team. He explained: "We had some niggles here and there in terms of getting the right cooling on the car, which we sorted.
“But then once we started to get going, we saw that we have work to do, because the car doesn't work as well as in the last events.
"We've just been taking a look, it's not a straightforward answer, I would say at this stage.”
He added: “Like all teams we could understand the peculiarities of this event, which is not only the venue, but it's also the behaviour of the tyres and the layout of the track.
“So it will be an interesting one. And I think we may see that the pecking order that can change quite dramatically as well."
Norris agreed that the team was likely to have a difficult weekend, adding: "I think we’re a long way off where we’ve been the last few weekends, but probably where we expected.
"It’s similar to where we were in Monza and other low downforce circuits. It’s a struggle at the minute, but I’m sure we can make progress into tomorrow."
