Mitchell Marsh's muscular medium fast bowling will lengthen Mitchell Johnson's reign of terror by shortening the length of his bowling spells. That is according to Australia's assistant coach Craig McDermott, who said Marsh's addition to the bowling attack was a critical ingredient in the tourists' resounding victory over England at Lord's.

Johnson's highly hostile performance was the most memorable element of Australia's bowling display in the second Investec Test, but his intimidation of England's batsmen was largely possible due to the effectiveness of the entire bowling ensemble. All improved notably on their displays in Cardiff, and Marsh's addition as an allrounder who not only soaked up overs but also threatened for wickets brought a tremendous sense of balance.

McDermott told ESPNcricinfo that Marsh was tracking to soon get his pace above 140kph (87mph) consistently, and that the more overs he could bowl at that kind of speed, the shorter and thus more devastating Johnson's spells could be. Able to be used in bursts of three and four overs by Michael Clarke at Lord's, Johnson recalled the havoc he wreaked in Australia in 2013-14.

"Mitchell Marsh's hard work over the last four months or so is really starting to pay off and going to strengthen us." McDermott said. "His approach to the wicket, his speed through the crease, and his pace is up, he almost clocked 140kph in the Test match. He's excited about being fit and swinging the ball while bowling fast. He's chasing 140 too, he wants to have a '4' in front of his number and that's good for us.

"If you've got an allrounder who's capable of bowling 140kph it certainly makes your bowling attack quite different. And the better he bowls the more he will be capable of doing in an innings, from 8-10 overs to 12-15, and that allows the other blokes like a Mitchell Johnson to bowl three or four over spells and just be on the money, bowling fast all the time. It changes Pup's dynamics quite a lot as a captain."

Australia's metamorphosis from uncertainty in Cardiff to the confident strut of Lord's came about as a result of strong first-innings runs from Chris Rogers and Steve Smith, which put the bowlers in their preferred position of attacking the batsmen when under pressure from the scoreboard. McDermott reckoned that while this was helpful, the pacemen could now be expected to be far more incisive if asked to bowl first.

"I think we'll be better for the gallop that we had in the first Test and I think the way they've produced the wickets they've produced certainly favours the team batting first," he said. "But if we bowl the way we did second innings at Lord's, whether we bowl first or second, we're going to knock teams over. We're in the right gear now so we've just got to keep going.

"In Cardiff we bowled too much on both sides of the wicket. We didn't bowl terribly but we didn't bowl well either, and we didn't really get the rub of the green. But we didn't bowl as well as we have done in the past 18 months and it was more a question of us getting back to the way we bowl well, and that's to bowl aggressively, hit our lengths regularly and get our short stuff right.

"One of the things we spoke about was that we're not used to the ball swinging all the time in Australia, so that was another thing we struggled with in the first Test match where we were swinging the ball back into the left-handers but it was coming into middle and leg instead of at off peg. Guys have to get used to that and I think bowling out in the middle helped us do that, getting more and more used to bowling with the Dukes."

The best example of improvement when bowling to a single batsman was in how the Australians effectively corralled Joe Root at Lord's after he clattered them in both innings of the Cardiff Test. Bowling fuller and tighter to off stump while offering Root the chance to force the ball through attacking fields resulted in a pair of low scores and a dent in the batsman's previously buoyant confidence.

"We didn't bowl well to Joe Root when he first came out to bat in both innings in Cardiff, we bowled too short, too wide and that's his bread and butter," McDermott said. "We got it right at Lord's, and we'll continue in that vein for a number of their players. They came unstuck against some aggressive bowling, so we're back in the frame of mind of the way we bowled in Australia last time and hopefully it's the start of doing that for the remaining three Test matches.

"You've got to be disciplined, you've got to be prepared to be boring sometimes. If players are playing well you've got to start to drag it back, and that's where you try to get your back-to-back maidens and that sort of thing. But at the same time we've got to be upbeat and do what we do best. The Australian bowling attack has always performed better when its been in that mode, rather than try to defend."

Johnson, Mitchell Starc, Josh Hazlewood and Nathan Lyon are all sitting out the tour match in Derby. McDermott said that Starc's ankle problems in Cardiff had settled down nicely, though he would more than likely need surgery for the joint at some point after the Ashes tour is concluded.