However, Arsenal were made to pay for their sloppy passing at the other end in the 44th minute, after Monreal gave the ball away needlessly in a risky area.
However, Alex Iwobi and Henrikh Mkhitaryan were named in the starting XI, with Arsenal confirming the playmaker was suffering with a back problem.
Lacazette was at the center of Arsenal's powerful show at Craven Cottage.
Alexandre Lacazette scored twice for the Gunners before Aaron Ramsey's brilliant finish and Pierre-Emerick Aubameyang's late double secured a third straight away win in the top flight - their best such run since October 2016.
On his potent strike-force, Emery added: "It is one process, to know better after training, after every match, after every decision, how we are better on the pitch, between the players, in our tactical system and impose our timing on the pitch in possession with the ball".
Mattis: US relations with China not worsening
Mattis this week acknowledged "tension points" between the US and China, but told reporters he did not "see it getting worse". Navy appear to show the Chinese warship pulling in front of USS Decatur , which veered off to avoid a crash .
"But I am just thinking about the next match against Leicester at the Emirates, in our home, with our supporters". We need to improve quickly on this. The Gabonese global, Pierre-Emerick Aubameyang was only among bench players in this game but he came on as a substitute in the second half to add two impressive goals to his goal tally this season.
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, who came off the bench in the 60th minute, piled more misery on the opponents with a flawless backheel. But the second half they scored very easy goals.
The Gunners have not enjoyed such a lengthy winning streak in 11 years but, despite being slow out of the traps, Alexandre Lacazette's brace set them on course for a 5-1 Premier League win to move them above neighbours Tottenham and into third place. They have the capacity to play lots of matches.