After the drawn second Ashes Test, England captain Joe Root said that Jofra Archer has changed the dynamic of the series.
Root is correct. Even on debut, pace bowler Archer has given England a real lift.
Following the first Test at Edgbaston, which Australia won by 251 runs, England supporters will have been thinking that the rest of the summer could have turned out to be quite horrible. There were even some murmurings of 5-0.
England had lost James Anderson, their all-time leading Test wicket-taker, to injury. They couldn't get Steve Smith out and had been forced to drop Moeen Ali.
Archer turned up at Lord's and snatched the initiative. He has shown what impact proper pace bowling can have.
He struck Smith, the best batsman in the world, under the ear after he had been at the crease for four hours. It was a blow that ultimately meant Smith had to withdraw from the match with concussion.
The effect that will have not only on Smith, but also his team-mates, will be immense.
Along with Ben Stokes, who made a lovely century on the final day, Archer gave England a real chance of winning the second Test, even after more than five sessions were lost to rain.
Yes, England's first-innings batting was a disappointment, but they came out of the match ahead. They may be frustrated that they didn't manage to win it, but by the end they were holding the upper hand. How many of us expected that after Edgbaston?
Suddenly, it is England who look reinvigorated and Australia who will be pleased to get out of Lord's intact.
It is the tourists who have thinking to do before the third Test at Headingley begins on Thursday. What are they going to do about Archer? They know what to expect - plenty of hostility - but knowing what you're getting and actually being able to deal with it are two different things.
As for Smith, I hope he can play, because you don't want to see great players missing out through injury.
Having said that, if there is any doubt over his health, he should be forced to sit out.
And, if he is absent, and the weather allows five clear days of play, what an opportunity it will be for England to level the series.
Archer dismisses Warner as England chase victory
However, just because Archer has given them this new edge and there are questions over Smith, we shouldn't expect everything to go smoothly for England from here.
When you have two batting line-ups as eccentric as those of these Ashes rivals, the series will continue to ebb and flow, the initiative will constantly shift direction.
These low-scoring games are dramatic and they move along quickly. They might frustrate those who long for old-fashioned Test batting, but there is no denying that they provide plenty of entertainment.
What might England do about their batting? Given the short turnaround, I suspect they won't tinker and, because they had the better of the game at Lord's, that is probably the correct decision.
Opener Jason Roy had a poor game, with two low scores, two poor dismissals and a dropped catch off Travis Head at second slip on the final evening.
When Roy was picked, and most were in agreement that his white-ball form warranted a chance at Test cricket, we made a collective pact.
We knew he was chosen for the times he will come off, when a swashbuckling Roy innings can change a game, especially a low-scoring one, in the space of a session. We also knew that there would be times when he leaves us scratching our heads.
For that reason, England must be patient, and not discard him after three caps. He could yet play a match-winning innings in this series.
Similarly, Joe Denly has hinted towards being able to cut it at Test level. When I saw him on the final morning, he said he was fed up with making "pretty 20s". I told him that was better than making an ugly nought. He will be feeling under pressure to convert.
For the problems England have in their top four, further down they have been boosted by the return to form of Jonny Bairstow and Jos Buttler, as well as that lovely hundred from Stokes.
In many ways, Stokes does bat like an old-fashioned player. He gets himself in - which cannot be said of some of his peers - with careful defence and patience.
But, when he his in, he can cut loose, just like he did at Lord's on Sunday. He played some wonderful strokes.
So, there was a lot that went right for England at Lord's, but they are still 1-0 down with three Tests to play and, with the nature of Ashes cricket being the holders retain the urn if the series is drawn, England cannot afford to lose any of the last three Tests. That is a big ask.
Potentially, they are one batting collapse away from the Ashes heading back down under.
They must win at Headingley, and possibly again at Old Trafford, to set up a grandstand finale at The Oval.
Wouldn't that be something?