Bukayo Saka's first-half strike earned Arsenal a crucial 1-0 win at Brighton as they took full advantage of Manchester City's shock 2-2 draw with Nottingham Forest to move seven points clear at the top of the Premier League. Mikel Arteta's side were far from their best at the Amex Stadium, but Saka's ninth-minute effort gave them something to hang onto, and with Gabriel Magalhaes colossal at the back they ground out a huge win on what could prove to be a pivotal night in the title race.Having secured back-to-back victories in London derbies, this was always going to be a huge game for Arsenal as they looked to at least maintain their advantage over City ahead of the FA Cup fifth-round weekend. And, after surviving an early scare when Gabriel was forced to head off his own line following a poor clearance from David Raya, they hit the front through Saka.Making his 300th appearance for his boyhood club, Arsenal's stand-in skipper for the night cut in from the right having received a pass from Jurrien Timber and fired in a shot which took a deflection off Carlos Baleba and deceived Bart Verbruggen in the Brighton goal.Arsenal struggled to build on that opener, with Brighton causing them plenty of problems in the first half, but the visitors survived some nervy moments to take a firm grip at the top of the table thanks to Nottingham Forest's heroics in Manchester.GOAL rates Arsenal's players from the Amex Stadium...David Raya (7/10):Bailed out by Gabriel after an awful early error. Settled well after that though and looked after his box well.Jurrien Timber (7/10):Another goal contribution with an assist for Saka. Solid as always down the right.Cristhian Mosquera (7/10):Came in for the injured Saliba and picked up an early booking. Handled the situation pretty well, though, and made some crucial interventions. Gabriel Magalhaes (9/10):Cleared one off the line in the first few minutes and that set the tone for what followed. Threw himself in front of everything. Colossal. Piero Hincapie (8/10):Another excellent display from a player in form. Not much impact in attack, but defended well and was superb when he moved to centre-back in the second half.Martin Zubimendi (6/10):A player who just looks like he needs a proper break. Taking too long when he is on the ball and looks far more uncertain during his first few months in the Premier League.Declan Rice (7/10):Another game where he made some individual errors. He salvaged them himself at times with some fine tracking back and was really important in the second half.Eberechi Eze (6/10):Played one nice pass to release Saka early on, but couldn't really get on the ball to make things happen after that. Bukayo Saka (7/10):Marked his 300th game for Arsenal with an early goal. Got a bit of luck with the deflection, but it was good to see him take the shot on.Viktor Gyokeres (5/10):Struggled in a game that was not played to his strengths. Kept having to battle for long balls with his back to goal and Brighton dealt with him comfortably.Gabriel Martinelli (5/10):No real impact. Worked hard as always, but carried no threat down the left.Add GOAL.com as a preferred source on Google to see more of our reportingKai Havertz (6/10):Gave Arsenal more control up top, which helped them get much needed spells of possession in the Brighton half. Leandro Trossard (5/10):Was given a tough time by the Brighton fans, who particularly enjoyed one miscued shot which went out for a throw.Riccardo Calafiori (6/10):His introduction did allow Arsenal to have more joy in midfield with the way he was inverting.Christian Norgaard (N/A):Replaced the tired Zubimendi for the final 10 minutes.Mikel Arteta (7/10):He can't have been happy with his team's first-half performance. His changes after the break did lead to an improvement, however.