Yorkshire arrived at Edgbaston for this Specsavers County Championship Division One match still without injured front-line seamers Jack Brooks, Ryan Sidebottom and Liam Plunkett.
But captain Gary Ballance happily took up the option to bowl first and Coad led the dismantling of the home side’s top and middle order.
The 23-year-old, playing only his fifth first-class match, followed up his 6-37 against Hampshire at Headingley last week with 4-47 as Warwickshire made 152-8 on a day stripped of almost exactly half its scheduled overs by rain.
For the home side it was another worrying day.
Having taken just a single point from their opening game against Surrey at The Oval, where they were bowled out in the first innings for 91, the Bears were in danger of coming in under 100 again at 77-7 before Keith Barker (33 not out, 58 balls) and Jeetan Patel (36, 30 balls) counter-attacked.
Yorkshire, who also lost their opening game last week, welcomed David Willey back into their bowling attack but it was Coad who inflicted serious early damage with a burst of 3-12 in his first eight overs.
He removed William Porterfield, caught by Ballance at mid-off and Alex Mellor via a catch by wicketkeeper Andrew Hodd before trapping Jonathan Trott lbw.
Tim Bresnan and Steve Patterson constitute a high-class pair of change bowlers and both struck quickly, the former trapping Sam Hain and the latter luring Ian Bell into a drive which he edged to the wicketkeeper.
When, just after lunch, Patterson had Tim Ambrose caught behind and Coad trapped Rikki Clarke lbw, Warwickshire were 77-7 but Patel and Barker built a run-a-ball half-century partnership.
The counter-attack proved effective, Patel hoisting Coad over mid-wicket for six, before it was first halted by rain and then terminated in the second over after the resumption when the New Zealander was bowled by an Adil Rashid googly.
Barker and Chris Wright added an unbroken 20 to preserve Warwickshire’s hopes of harvesting their first batting point of this season. But too many of their colleagues had, like Hampshire’s batsmen last week, failed to crack the Coad.
Afterwards, Coad admitted he was enjoying his promising start to the 2017 campaign, particularly given the competition that will only increase as injuries subside.
“It’s coming out well for me,” said Coad.
“I’m just happy to be putting into practice all the work I did during the winter. It was good to get Jonathan Trott out. He was one of the ones, him and Bell, the two big names that I wanted.
“It’s easy to bowl alongside players like Tim Bresnan and Steve Patterson because they do their jobs day in and day out and if you need any help, they are there to help you out, It is great to have that.
“It was frustrating that they put on a little partnership but we bowled well all day.
“There is always going to be a partnership here or there so we have just got to keep doing what we do.”
Warwickshire’s Barker acknowledged the effectiveness with which the visitors had bowled on the opening day.
“The wicket did quite a lot more than I thought it would, to be honest,” he said.
“They bowled very well, kept their line and lengths and really tested us with the ball. There was some swing but also some nice nip there, especially for Coad. he was the standout bowler for them.
“They have still got big players missing from their normal starting XI so it shows the depth they have got.
“There is movement off the wicket and in the air so it was quite testing. But there should be a bit more weather around in the match so hopefully it will be there for us when we bowl.
“The counter-attack was more Jeets than me. Jeets seemed to be able to take it to them a lot easier than I was able to. It was just a shame we lost him straight after the rain-break.”