Gareth Southgate feels England "still have work to do" defensively in order to compete for the Euro 2020 trophy next summer, despite beating Montenegro 7-0 on Thursday.
The Three Lions booked their place in next summer's tournament with a comprehensive victory against the Group A minnows at Wembley.
A Harry Kane hat-trick plus goals from Alex Oxlade-Chamberlain and Marcus Rashford gave England a 5-0 lead at the break, which allowed the home side to let their foot off the gas in the second period.
Kane's latest treble took him to sixth in England's all-time scorer's list, with 31 to his name from 44 outings in total.
Southgate's side were gifted a sixth goal when Aleksander Sofranac put through his own net just after the hour mark, before substitute Tammy Abraham rounded off the scoring late on.
England were often scintillating going forward, but Jordan Pickford was forced into action on a couple of occasions, with John Stones and Harry Maguire guilty of some lackadaisical defending.
When asked post-match what pleased him most about England's latest display, Southgate pointed to the "super quality" on show in the final third of the pitch, before highlighting his team's fragility at the back.
“The attacking playing in the first half, in particular,” Southgate said. "Really good movement and super quality of passing and crossing, and really good finishing.
"We know we should win the group comfortably but you look around Europe and there are other countries who struggle to score the goals that we have.
"In the past, we have struggled against those lower ranked teams who defend in numbers, now we've got players that can open these teams up and a style of play to match.
"[But] we have to get both ends of the pitch right. We conceded a couple of chances tonight that we shouldn’t have.
"They're the clinical things we'll have to be better at. There's still work to do without the ball, but we are improving."
Tonight's result means England maintain their three-point lead at the top of Group A, with the Czech Republic also through to Euro 2020 after beating Kosovo 2-1 at home.
The Three Lions will wrap up their qualifying campaign with a trip to Kosovo on Sunday.