“We’ve found a way to break them down, which maybe in the past we haven’t.”
Southgate again put his faith in youth, with the starting line-up’s average age of 23 years and 255 days making it the youngest Three Lions side since 1959.
As expected, Manchester City’s Raheem Sterling was left out by Southgate as punishment for his role in an altercation with Liverpool’s Joe Gomez at England’s training camp on Monday. Gomez was booed by some fans at Wembley when he entered came on as a substitute.
“No England player should ever be booed. We are a team and Joe has done nothing wrong, I made that clear earlier in the week so I don’t understand that,” Southgate said.
Sterling added on Twitter: “To all the England fans, I wanted to leave things as it was but tonight I have to speak again: it was hard for me to see my team mate get booed for something that was my fault.
“Joe hasn’t done anything wrong and for me to see someone who keeps his head down and works hard, especially after a difficult week for him, to be booed when he came on tonight was wrong.”
Even without Sterling, England have no shortage of options in attack with Jadon Sancho and Marcus Rashford lining up alongside Kane in a three-pronged attack.
Alex Oxlade-Chamberlain, whose progress with the national team has been hampered by injury, put England ahead in the 11th minute, drilling into the bottom corner after left back Ben Chilwell found him with a clever chip over the defence.
Leicester City’s Chilwell created the second seven minutes later with a free kick that picked out Kane, who smartly glanced home a header.
The same pair combined for the third with Kane losing his marker to head in a corner from Chilwell.
Manchester United striker Rashford drove home the fourth, after Montenegro goalkeeper Milan Mijatovic parried out Harry Maguire’s header.
Kane wrapped up his hat-trick in the 37th minute, with a sharp turn and shot into the bottom corner as England went into the break 5-0 up.
“We have had one slip-up in the group and responded really well. Got the job done and wanted to put on a show in our 1000th game and with five goals in the first half I think we did that,” said Kane, who moved up to fifth in England’s all-time top-scorer rankings.
An own goal from Aleksandar Sofranac made it six after a scramble in the box.
Substitute Tammy Abraham grabbed his first England goal, six minutes from the end, sliding in at the near post to convert a low cross from Sancho.
Elsewhere, Portugal captain Cristiano Ronaldo scored another treble, moving closer to 100 international goals, as he led the European champions to a 6-0 drubbing of Lithuania.
Ronaldo, whose hat-trick was the 55th of his career and ninth for Portugal, has 98 goals and could become only the second player to score a century for his country after Iran’s Ali Daei.
Pizzi, Goncalo Paciencia and Bernardo Silva shared the other goals in the one-sided group B match.
The European champions, however, were left waiting to secure a place at the finals after Serbia beat Luxembourg 3-2. Portugal are in second place with 14 points, one ahead of Serbia, and will qualify if they win in Luxembourg on Sunday. Leaders Ukraine have already qualified.