Arsenal moved closer to the Premier League title in controversial fashion as a hugely contentious decision to disallow Callum Wilson's stoppage-time goal handed the leaders a vital 1-0 win against West Ham on Sunday.
Mikel Arteta's side struggled to break down West Ham in a tense derby at the London Stadium before Leandro Trossard struck with a deflected effort seven minutes from fulltime.
But Arsenal's title rivals Manchester City will be furious that West Ham were denied a last-gasp equaliser for Pablo's foul on Gunners keeper David Raya, whose fumble was fired home by Wilson.
Pablo had his arm across Raya's chest in the incident but the contact was minimal, with West Ham also claiming fouls by Declan Rice and Trossard at the same moment.
In what could be the defining image of the title race, referee Chris Kavanagh and the VAR officials took an age to disallow the goal, with the verdict eventually sparking outraged jeers from West Ham fans, while Arteta clenched his fists in relief.
Arsenal are five points clear of second-placed City, whose 3-0 win against Brentford on Saturday had kept the pressure on the leaders.
City can close within two points of Arsenal if they win their game in hand at home to Crystal Palace on Wednesday.
But Arsenal know they are guaranteed to seal the title if they win their last two games against Burnley and Crystal Palace.
The Gunners' mental strength has been questioned numerous times in recent years, but they showed spirit and desire in equal measure to edge ever closer to a long-awaited first title in 22 years.
Arsenal have also reached their first Champions League final since 2006, beating Atletico Madrid in the last four on Tuesday, and will face Paris Saint-Germain in the final in Budapest on May 30.
Winning their 14th English title and a maiden Champions League crown would make it the greatest season in the club's 139-year history.
Thierry Henry, a key figure in the unbeaten "Invincibles" side who were the last Arsenal team to win the title in 2003-04, recently said Arteta's squad would be known as the "unforgettables" if they lift both trophies.
For the thousands of Arsenal supporters crammed into one end of the London Stadium, this was a result they will never forget if the title is secured over the next two weeks.
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Third-bottom West Ham's hopes of avoiding relegation are fading.
They are one point behind fourth-bottom Tottenham, who can take a huge step towards survival if they beat host Leeds on Monday.
Trossard went close for Arsenal from an early corner, his close-range header well saved by Mads Hermansen before the winger headed the rebound onto the crossbar.
Arsenal suffered a blow when Ben White limped off midway through the half, forcing Rice to move from midfield to a makeshift right-back role.
After being penned in for so long, West Ham were inches away from taking a shock lead just before halftime.
Valentin Castellanos threw himself at Aaron Wan-Bissaka's cross with a diving header that Raya saved at full stretch.
Arsenal had lost control of the game with Rice out of position and Arteta responded at the break, sending on Cristhian Mosquera so the England star could return to midfield.
Even that couldn't shift the momentum back in Arsenal's favour.
Raya made a brilliant save to keep Arsenal level, sticking out his foot to block Mateus Fernandes' shot after the midfielder looked certain to score from five yards.
It was a priceless contribution as Arsenal netted in the 83rd minute.
Martin Odegaard played a one-two with Rice and cleverly worked the pass into Trossard, whose strike from 12 yards took a hefty deflection on its way past Hermansen.
There was nearly a sting in the tale for Arsenal when Raya's drop was lashed in by Wilson, but VAR came to the Gunners' rescue, leaving them three wins from immortality.