Lewis Hamilton says Mercedes cannot afford to have another race weekend like Monaco if he is to mount a successful title challenge against Red Bull's Max Verstappen this year.
Hamilton lost the lead of the championship for the first time in 2021 last weekend after he finished seventh and Verstappen won the race.
The seven-time world champion struggled for performance throughout the weekend, qualifying seventh and then failing to capitalise on the misfortune of Charles Leclerc and teammate Valtteri Bottas.
He lessened the blow slightly by picking up a bonus point for fastest lap, but now trails Verstappen by four points in the driver standings after five races.
"I told you at the beginning they [Red Bull] have got a championship-winning car, and they're going to be very hard to beat," Hamilton said.
"I've been serious about it all year and we've won races which we shouldn't have won, like in Bahrain, but it's not over.
"There's a long long way to go, but we can't afford another weekend like this.
"I'm grateful I finished and got some points, fastest lap, every point you get on a bad weekend like this can hopefully count towards something at the end."
Mercedes technical director James Allison said the mood in the team was "lower than a snake's belly" on Sunday night, and called the race "a screw-up".
The lack of performance was rooted in tyre temperature as the drivers struggled to match front and rear tyres for a quick qualifying lap, which left Hamilton seventh on the grid and Bottas third.
In attempting to combat the issue by tweaking the setup, Mercedes then lost performance in the race with a car that chewed through its tyres too quickly over a longer run.
Allison said the team had struggled with similar issues in recent years at Monaco, but that the car's overall performance advantage meant the problems were less obvious.
"If you are a proper anorak and you look at our team's performance at this track over the last several seasons, you would see that in year's where we won the championship with ease, we nevertheless struggled here," he said.
"Although we have generally been on a path that has delivered a car that is a broad-sworded weapon that you can attack most tracks with, this circuit has been a particular Achilles heel.
"And particularly ironically, one of our car's best weapons this year has been its usage of its tyres circuit after circuit after circuit, but at this particular track we always struggle with that and we are never really getting them happy on a Saturday.
"So our grid slots are lowly and on Sunday, although we are OK at the start of the stint, at the end of the stint when most of the crucial action takes place at this rather particular track -- where there isn't much opportunity for overtaking except for around that first stop -- we are normally all out of ideas with a tyre that has died a little sooner than our competitors.
"And it's understanding that that we have failed to do for a number of seasons, and we need to figure out from first principles what we are getting wrong and what it is that we are doing year on year that is just not right here."
Although Hamilton struggled to a seventh place finish, teammate Bottas looked set to finish in second place before a problem with the right front wheel nut at his pit stop forced him to retire.
Asked why Bottas outperformed Hamilton by such a margin in Monaco, Allison added: "He was able to get the front tyres happier at the beginning of the lap than Lewis and then had more confidence to welly into the lap and take the car near the barriers, which is what you need to do to get a good lap out of the thing round here.
"So objectively there was a bit of difference between the temperature of the front tyres between the two cars, but both drivers were basically suffering with the front tyres coming into their best operating window later than the rear tyres."
Hamilton said he would take part in two engineering meetings this week to help the team understand the issues and work toward a solution.
"For whatever reason we couldn't get out tyres working the way that others could," he said.
"At the same time Red Bull have really good race pace and that's a big, big question of how we utilise the tyres on tracks like this.
"On the last races we've generally been good on tyres but this one particularly we've been weak. That's an area we need to understand and rectify for the future.
"This has never generally been a track for us, we have the longest car, it's like a bus to turn through the corners, it's not as nimble on a small track like this but it's great elsewhere.
"There are things that don't work here which bode well for the other circuits.
"I'm sure the guys will blow off some steam, see their families, but will be back at the factory tomorrow.
"I'll be invited to a meeting probably Tuesday, then another one later in the week, to analyse for the next one."