Historically, the first international games after a major tournament are usually either dreary or one-sided affairs (or, in the worst cases, both) as countries regroup from the success, failure, or ambivalence of their summer performances.

For instance, in the first fixtures after both England and Spain bombed to group-stage exits at the 2014 World Cup, the former beat Norway 1-0 at Wembley thanks to a Wayne Rooney penalty in a clash that thrilled and intrigued precisely nobody in the sparse crowd, while the latter looked flat in a 1-0 defeat to France. Then, after Euro 2016, at which both nations fell in the last-16, the Three Lions required a 95th-minute Adam Lallana winner to beat 10-man Slovakia, while La Roja coasted to a 2-0 win over Belgium.

This time, however, things could – and, hopefully, will – be different. As the two countries meet in their UEFA Nations League opener Saturday at Wembley, both are kicking off new eras in more ways than one.

For each, a primary focus is reinvigoration.

After the post-World Cup international retirements of Jamie Vardy and Gary Cahill, and Gareth Southgate’s eschewing of Ashley Young, England’s squad does not contain a single player over the age of 28. It is a remarkable quirk representing an entirely intentional move from the former Under-21 team’s coach to place his focus solely on burgeoning and peak-age talent. Southgate has selected two uncapped goalkeepers in Alex McCarthy and Marcus Bettinelli, while six other inclusions are yet to reach double figures in games played at the senior international level.

“We only have 20 matches between now and the (2020) European Championships, so we don’t want to waste time looking at new things (but) to embed principles that are going to be with us over a period of time,” Southgate said.

England reached the semi-finals in Russia this summer, its best World Cup finish in 28 years. However, in reality, it beat teams it should have beaten, won a lottery against Colombia, and lost to two sides it would like to think it could have beaten: Belgium and Croatia. A victory over Spain, regardless of the recent turmoil on the Iberian Peninsula, would represent a clear sign of progress for Southgate’s men.

“We’ve got to keep the momentum,” said goalkeeper Jordan Pickford. “This Nations League thing, I think, is a really good showcase for England against the top teams in the world, and we want to be beating those top teams.”

Meanwhile, Spain, which will be led for the first time by Luis Enrique, has selected four players aged 30 or older, but that is something of a red herring. Aside from centurions Sergio Ramos and Sergio Busquets, who boast 263 caps between them, only Raul Albiol – returning to the fold for the first time since 2015 – has more than 33 international games under his belt.

Gone are veterans Gerard Pique, David Silva, and Andres Iniesta – all key staples of the side for the last decade who retired from the international game this summer. Enrique has overmatched Southgate by selecting 11 players yet to hit the 10-cap mark, though Valencia’s Rodrigo, at the age of 27, will reach that tally if he makes it onto the pitch.

While Southgate’s foremost mandate will be to preserve the rather unexpected ebullient mood brought on by England’s (relative) success in Russia, Enrique’s task is far greater. The former Barcelona manager must undertake a significant rebuild after a disastrous summer for the nation both on and off the field. The mess of Julen Lopetegui’s departure has not been forgotten, and it will take a giant leap forward to begin the reformation process.

However, remarkably, given the huge disappointment of a third consecutive early major-tournament exit, Spain is unbeaten – outside of this summer’s penalty-shootout defeat to hosts Russia – since June 2016. Enrique has made some big selection calls, dropping longtime first-choice left-back Jordi Alba (thus facilitating the return of oft-overlooked Chelsea man Marcos Alonso) and Atletico Madrid star Koke.

He’s made notable off-field changes, too, with a renewed focus on punctuality and discipline, and that includes banning the use of mobile phones during team meals. Some players will like those rules, others won’t. Real Madrid star Isco is one who agrees.

“It’s always important to have a little discipline,” the midfielder said. “I think the decision to stop using mobiles during meals is good because at times you are more focused on machines than speaking to a teammate.”

Enrique will bring a new style, eradicating many of the remnants of tiki-taka and implementing a more pragmatic approach. Should the results be underwhelming (and even, perhaps, if they are glowing), those changes will likely prove unpopular with many Spaniards.

Southgate’s task after years of hard-to-stomach stagnation is to maintain and magnify the unfamiliar feeling that has grown like a root across England this summer: positivity. Enrique’s assignment? To prove to a disenchanted nation that optimism can still exist.

Predicted lineups (number of caps in parentheses):