On the opening day of last season, the 19-year-old trotted out for his Premier League debut as Southampton won 1-0 at West Brom.
Less than 14 months has passed since then, during which time Chambers has made a £16m move to Arsenal, featured regularly in the Champions League and played for England.
The versatile defender made his Three Lions debut off the bench in last month’s uninspiring friendly against Norway, but looked like he would have to wait for his second senior cap after dropping down to the Under-21s for European Championship play-off with Croatia.
However, an injury to former Barnsley defender John Stones saw Chambers bumped up by Roy Hodgson on Sunday and led him to make his full debut in the Euro 2016 qualifier against San Marino just four days later.
“It is amazing,” Chambers said. “I got named in the England Under-21s and they have got two tough games coming up, which would have been a good experience.
“But then I got called up to the first team, which is an amazing feeling and especially to get my start. It has been a fantastic couple of days.
“It has been a mad start of the season for me, but I’ve got to keep going, keep concentrating and just try to keep improving on my game the best I can.”
Chambers knows significantly tougher battles lie in wait, given Thursday’s opponents sit bottom of the world rankings alongside Bhutan.
Still, it was a sturdy display both individually and collectively as England overcame the San Marinese 5-0 at Wembley.
“We knew we had to go into the game and give it everything,” Chambers said. “We had to move the ball quickly.
“It wasn’t going to be easy at the start. The first half was a bit frustrating.
“They were tough to break down but eventually the things we worked on the training pitch got into the game and we got the goals in the end.
“We’re pleased with the performance. It is a good win at the end of the day. We can take a lot of positives from that game. I thought we did well.
“We’ve got another coming up. We will get back, rest and get ready for that.”
Despite having predominantly been deployed at centre-half by Arsenal, Chambers returned to his more regular position of right-back against San Marino.
The 19-year-old was given the nod ahead of former Southampton team-mate Nathaniel Clyne and, with Stones, Glen Johnson and Kyle Walker all injured, appears to have the chance to establish himself.
“I don’t know,” Chambers said. “That’s not up to me. All I can do is play the best I can to get the opportunity to get picked for that.
“I go into training and games and give it 100 per cent to give myself the best opportunity to do that.”
Adam Lallana described Chambers’s bow a “magnificent” full England debut.
“He was magnificent,” England midfielder Lallana said. “It was not an easy game for him.
“He was always going to have lots of the ball and take risks with his passes because that’s what happens against teams that camp behind the ball.
“He showed great composure and is going to go on to have many, many more caps.”
Lallana knows Chambers better than most, having played alongside him at Southampton.
He made his England debut from the bench against Norway last month. “I knew it was a matter of time before he possibly moved on or went to a big, big club,” Lallana said.
“It hasn’t surprised me at all how quickly and how well he’s started.
“I was watching the Champions League qualification games and he took to them like a duck to water. He was brilliant, showed great composure and he can play centre-half as well. He is a very talented boy and it’s a great thing for England.”
Goalkeeper Joe Hart is likely to have been concentrating so hard in England’s 5-0 victory that he could have given himself a headache, according to former No 1 Ray Clemence.
Manchester City goalkeeper Hart was a virtual bystander, only touching the ball 19 times.
However, Clemence insists Hart’s contribution should not be taken lightly despite a perceived lack of match action.
Clemence said: “Although Joe had nothing to do, it was still a big test for him because you have 50,000 people there and you still have to concentrate for 90 minutes knowing that you might only have one save to make.
“I have been in that situation many times with England and also with Liverpool.
“I used to get really bad headaches after a game just through concentrating, shutting everything else out to make sure that I was switched on if I had anything to do.
“You try to shut everything else out and just play the game in front of you.”