After heading the Gunners in front after four minutes, Welbeck rounded off a fine team move for the second before the interval. Teenage prodigy Emile Smith Rowe makes his full debut for the first-team, starting in attack alongside the likes of Henrikh Mkhitaryan, Alex Iwobi and Danny Welbeck.
Emery said he was "very happy" with Welbeck when asked if he wanted the attacker to remain beyond the current campaign and praised the pressure he is applying to the established duo.
Lacazette also scored late for the Gunners on Wednesday after Alan Judge had made it a nervous second half for the hosts by pulling a goal back from a free kick.
"Like on Sunday, for example, after Sokratis" injury it was important how Rob played and helped the team to find the performance to win against Everton.
With Pierre-Emerick Aubameyang and Lacazette forming a budding relationship Emery is likely to keep the pair in the side for Saturday's visit of Watford - but the Spaniard insists Welbeck has thrown his hat into the ring.
"He's a great player, we see it every day in training and he's had lots of great performances in the under-23s", Welbeck told Arsenal's official website.
'There are three things when we are speaking about an individual.
"I know they are in the previous year and are speaking with the club".
'Also we can give players chances to play, chances to take confidence and minutes in the game.
"Tonight, it's a good performance from every player and also Danny Welbeck, he worked with two goals, helping us. We forced a very good team into mistakes and nearly took them to penalties at the end".