Arsenal head coach Mikel Arteta: "It was very cruel the way we lost it, in the first half we saw a lot of positives and saw what we are trying to implement. But the way we conceded was disappointing.
"It was clear why it was disappointing, I don't need to say any more.
"Our reaction was right, we were doing the right things, it is hard to dominate all periods of the game against this team. We started to defend too deep and our energy levels are in a different place to Chelsea's.
"We need to sustain those periods for longer periods in the game and against top sides. Individual errors cost you games but I can't fault the effort, commitment and for putting in place what we practised
"We were so awful for the first 30 minutes; slow, lethargic, nervous," Lampard told BBC Sport.
"We gave Arsenal everything they wanted. We made the change early, felt it had to be done, and second half we dominated.
"You can accept a miss-pass but you can't accept lethargy in a London derby. The players were told that and they delivered. The second half was nothing to do with tactics, it was all to do with spirit and desire."