One can't help but think how the mighty have fallen from looking at this weekend's Premiership action.

With Manchester City getting emasculated in a one-sided loss against Stoke and Manchester United getting another workmanlike 0-0 draw, the top teams seem to be in a deep funk. The most stunning result was neither of those, but Chelsea's loss to promoted Bournemouth. Loving all this are surprise Premier League leaders Leicester, who spent much of last season at the bottom of the league.

Arsenal jumped into second place, but they had to fight hard to beat Sunderland, with the 3-1 result flattering the Gunners. After having lost and drawn respectively to smaller teams in their previous two games, Arsenal certainly felt tremendous relief at the win, as ­Arsene Wenger admitted afterward.

Indeed, when Sunderland equalized just before the end of the first half, Wenger and Arsenal fans must have felt a sense of dreadful deja vu because the same thing happened against both West Brom and Norwich, with the former scoring a second goal to win 2-1. The fragile state of the team could be seen when Wenger substituted Calum Chambers and Kieran Gibbs into the game late in the second half, which meant Arsenal had six defenders on the pitch.

Fortunately, Arsenal had no injuries in the Sunderland game after losing three players against Norwich a week ago, with midfield dynamo Santi ­Cazorla injuring a knee ligament and being out for at least three months. The team are bravely battling on but clearly running on fumes, forcing Wenger to mix and match the team formation.

Against Sunderland, Joel Campbell, who normally plays as a forward, started on the right wing before being switched to the left. The move worked as Campbell ended up scoring his second league goal this season. Meanwhile, with Cazorla, Alexis Sanchez and Francis Coquelin out, Mesut Ozil is playing in the form of his life and carrying the team. Ozil supplied the assist for Arsenal's first goal against Sunderland, his 12th assist this season. One shudders to think where Arsenal would be without him, and every fan must hope Ozil does not get injured.

With the big teams all in a precarious state - Arsenal ravaged by injury, City inconsistent, United with a superb defense and an impotent offense, and Chelsea still in the bottom half of the ­table - Leicester's miraculous run is looking less and less like a fluke. Next weekend, they face Chelsea - who are on the ropes - in what should be a crucial game for both teams, but for different reasons.

The author is a Beijing-based freelance writer. hcpyip@gmail.com