Liverpool, who remain unbeaten in their last 18 home games against City, came out roaring and dominated the opening 10 minutes but Pep Guardiola's visiting side weathered that early storm and were the more unsafe after the break.
The former Borussia Dortmund forward completed his epic brace at stoppage time after being perfectly set up by Ramsey.
Manchester City, Liverpool and Chelsea are all on 20 points after eight games played, with Arsenal on 18 in fourth place.
The Gunners are growing in confidence under Emery and are undoubtedly on track for a top-four challenge, while Lacazette's form comes as a major plus.
The Germany global split the two Arsenal centre-backs and his deft lob from Vietto's slide-rule pass deservedly saw Fulham draw level just before the interval.
Turkey's President Recep Tayyip Erdogan opens mosque in Cologne
The case has strained ties between North Atlantic Treaty Organisation allies Turkey and the US. Hundreds of anti-Erdogan demonstrators gathered at a separate area.
Lacazette was at the centre of Arsenal's powerful show at Craven Cottage, with his superb second-half strike restoring their lead after Andre Schurrle had cancelled out his opener.
Ream's first outing this season ended in a 3-0 loss to Everton, and this did not go any better for the United States defender.
"Aaron Ramsey sent a clear message as he gestured with his outstretched arms in celebration of his wonderful goal at Craven Cottage", he told the Daily Mail. The Gabon striker wasn't finished yet and, in the last minute, he smashed in Ramsey's pass for his sixth goal of the season.
- Arsenal have a 51.5% win rate in Premier League London derbies (124/241) - the best in the division.
However, they invited Fulham onto them early on and Bernd Leno, who was making his first Premier League start, was abruptly forced into action.
Finally he met Pierre-Emerick Aubameyang's low cross with a delicate flick with the inside of his boot to beat Marcus Bettinelli in the Fulham goal and conjure memories of the sort of goals Dutch great Johan Cruyff used to score. They will play Leicester City after the worldwide break and will then make a trip to Portugal to play Sporting CP in the Europa League.