It is looking increasingly likely that Chelsea and Arsenal will be the teams from the Premier League's "Big Six" to miss out on Champions League qualification this season.
Chelsea lost in Manchester for the second straight weekend, defeated 1-0 at runaway leader Man City to drop five points adrift of the top four with nine games remaining.
Arsenal is eight points further back in sixth after a 2-1 loss at Brighton that capped a miserable 10 days for the London club, during which it lost four straight games across three competitions. Arsenal hasn't lost four matches in a row since 2002.
It was always going to be the case that two big-name managers would have their reputations damaged this season by missing out on the top four. Arsenal's Arsene Wenger might have been predicted, but surely not Chelsea's Antonio Conte.
Chelsea finished 15 points ahead of City last season in romping to the league title. Ten months later, City is 25 points clear of the soon-to-be-deposed champions.
Conte's post-match comments highlighted the gulf that has opened up between City, the leader by 18 points, and the rest of the league.
"At this moment, you have to accept every criticism," said Conte, who set up his team so defensively that Chelsea had just 22 percent possession in the first half. "But I'm not so stupid to play open and lose 3-0 or 4-0."
Chelsea got through that first half, only to concede within 33 seconds of the second half when David Silva crossed for Bernardo Silva to force in a finish at the far post.
City needs 12 more points to win the league, meaning the title could yet be clinched at home to Manchester United on April 7.
Arsenal conceded twice in the first 26 minutes at Brighton, both following errors by goalkeeper Petr Cech. Lewis Dunk and Glenn Murray were the gleeful recipients.
Pierre-Emerick Aubameyang replied for Arsenal just before halftime.
"It is very difficult, nearly impossible now," Wenger said of Arsenal's top-four chances, "we are too far behind. We need two teams to collapse, not one."
Given a run of starts for the first time this season, Bernardo Silva is finally showing why City paid 43 million pounds ($55 million) to Monaco for his services last summer.
The Portugal midfielder backed up his goal in the 3-0 win over Arsenal on Thursday with the winner against Chelsea. This was scruffier, a bundled finish at the far post from David Silva's square ball, but more important in the circumstances.
Bernardo Silva had to be content with a place on the bench for most of the first half of the season, with Leroy Sane and Raheem Sterling unstoppable on the flanks. They have both been injured since the turn of the year and Silva has made the most of his chance.
Such was City's control of the game that the team didn't miss injured holding midfielder Fernandinho, who has been a crucial figure for Guardiola this season. Ilkay Gundogan had the freedom of the Etihad, completing more passes (161) than any other single player in a Premier League game.
Another defeat for Arsenal. Another apologetic tweet from Petr Cech.
Just like after Arsenal's error-strewn 3-1 loss at Swansea in late January, Cech fronted up on Twitter to own up to his game-changing mistakes against Brighton.
"If you want to win a game away (from) home in the best league in the world," Cech wrote, "your GK can't concede 2 goals like I did today ... it's not possible ... The team fought back but the damage was done."
Cech was beaten to a high ball following a corner to the back post, and Dunk slotted the loose ball home from the edge of the six-yard box in the seventh minute. Murray made it 2-0 in the 26th when his header from Pascal Gross' pinpoint cross squirmed under the diving Cech.
Arsenal is in sixth place and set for another year out of the Champions League unless it can win the Europa League, to earn a direct passage to Europe's top competition.
Brighton moved into 10th place, seven points above the relegation zone in its first season in the Premier League.