After Forest sat deep and frustrated Arsenal in the first half, the Gunners came to life in the second as Gabriel Jesus first squeezed home past Matt Turner and then set up Bukayo Saka for a fine second.
Taiwo Awoniyi smashed home late on to give Forest hope of an unlikely comeback but Arsenal were good value for their win.
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They now have 46 points ahead of their clash at home against Liverpool on Sunday, while Forest sit just two points above the relegation zone after losing back-to-back games and three of Nuno Espirito Santo's first five games in charge.
Nottingham Forest vs Arsenal player ratings
Via our friends at FotMob.com you can see Jesus had a day as he was popping up everywhere and delivered when it mattered most.
Nottingham Forest head to Bournemouth on Sunday, Feb. 4, while Arsenal host Liverpool on the same day in a huge game at the top of the table.
Nottingham Forest vs Arsenal, live score: 1-2
Goalscorers: Awoniyi 89'; Jesus 65', Saka 72'
How to watch Nottingham Forest vs Arsenal live, stream link and start time
Kick off: 2:30pm ET, Tuesday (January 30)
TV Channel: Peacock
Online: Stream via Peacock Premium
Nottingham Forest vs Arsenal live updates! - By Joe Prince-Wright
Full time; Nottingham Forest 1-2 Arsenal
The Gunners hold on and that is the kind of win you need to grind out if you're going to win the Premier League title.
Awoniyi hooks it on goal but David Raya saves
What is going on here!? Forest have hardly been in this game but somehow they've nearly rescued a point. Arsenal have to have a word with themselves here. 2 minutes of stoppage time left.
Taiwo Awoniyi finishes - Nottingham Forest 1-2 Arsenal (89th minute, Awoniyi)
Now then. The Nigerian striker slots home late on. The ball bounces kindly to him in the box and he is the first to react and slams home. Game on!? Surely not...
Bukayo Saka finishes off counter - Nottingham Forest 0-2 Arsenal (72nd minute, Saka)
Montiel gives the ball away and Arsenal punish him ruthlessly on the counter. Jesus finds Saka and the English winger drills home a low shot. Gunners cruising.
Gabriel Jesus finishes superbly to put the Gunners ahead - Nottingham Forest 0-1 Arsenal (64th minute, Jesus)
What a lovely finish that is at the near post. A throw in from Zinchenko finds Jesus in the box and he somehow squeezes the ball through Matt Turner's legs. The USMNT goalkeeper isn't happy at all with that.
Half time: Nottingham Forest 0-0 Arsenal
Not a single shot on goal from either side in the first half. Underwhelming. Arsenal huffed and puffed but never really looked like breaking through. Forest were never really interested in getting out of their own half. Hopefully the second half improves. It has to. Right!?
Arsenal keep knocking at the door
Forest just can't get out of their own half and Arsenal are piling on the pressure before the break. A loose ball finds Saka in the box (not what you want if you're Forest) and his low shot is deflected inches wide of the post with Matt Turner beaten as he was going the other way. Forest are, somehow, hanging in there and it's still level.
How has that not gone in!?
Lovely play down the left sets Emile Smith Rowe free and his cross towards Gabriel Jesus hits a Forest defender and somehow deflects over the bar. It defies the laws of physics that the ball didn't hit the back of the net. The corner comes to nothing for Arsenal as Forest continue to drop deeper and deeper.
We are underway at the City Ground and, as expected, Arsenal have had the ball for basically all of the opening few minutes. Forest are sitting deep and looking to play it up to big Chris Wood to hold, and then go from there. It's a bold strategy but it's their best chance of getting something from this...
Nottingham Forest starting lineup
Turner — Montiel, Omobamidele, Murillo, Toffolo — Mangala, Danilo — Dominguez, Gibbs-White, Williams, Wood
Arsenal starting lineup
Raya — White, Saliba, Gabriel, Zinchenko — Rice, Smith Rowe, Odegaard — Saka, Jesus, Martinelli
Focus on Nottingham Forest, team news
There is so much uncertainty swirling around Forest given the charges against them and Nuno Espirito Santo is doing his best to steady the ship. Six players are away at the Africa Cup of Nations and Awoniyi's absence continues to hurt Forest in terms of taking their chances. On the counter they're a real threat but they have to shore things up defensively and it seems like they want to sign a new goalkeeper in the final days of the January window as USMNT's Matt Turner has struggled in recent months.
OUT: Ibrahim Sangare (international duty), Serge Aurier (international duty), Cheikhou Kouyate (international duty), Moussa Niakhate (ankle), Ola Aina (international duty), Willy Boly (international duty), Felipe (thigh), Nuno Tavares (loan - parent club), Divock Origi (groin)
Focus on Arsenal, team news
The Gunners were in full flow against Palace last time out but they did see both Declan Rice and Gabriel suffer small injuries. The duo should be fine to face Forest and Arsenal's 10-day break came at the perfect time as their squad is looking healed and ready for a big final few months of the season. Now, who will score the goals Arsenal need for glory in the Premier League and Champions League? Gabriel Jesus is playing well but hasn't been prolific, while Gabriel Martinelli, Leandro Trossard and Bukayo Saka are all expected to step up and deliver plenty of goals in the coming months.