First rule of Solheim and Ryder Cups: never light the fire of moral indignation in your opponent's belly.
It's a history lesson which every captain should make every player sit - and this year's American captain Pat Hurst ought to know that better than anyone.
Because ahead of, and during, every golfing battle between the old world and the new the question of who will win is discussed almost as fiercely as the golf itself.
World rankings, history, Major Championship success, individual records, captaincy decision, foursomes partnerships, even, in this age of data, player fondness for right-to-left or left-to-right holes - they are all debated and deliberated to the nth degree.
But since the 1980s one factor has had a 100% success record: righteous fury inspired by the opposition's actions.
In the Ryder Cup, Europe's renaissance in the 1980s was inflamed by Severiano Ballesteros' perception of long-term American disrespect, Team USA's victory in 1991 was in some part a response to Ballesteros' on-course shenanigans, Europe's victories in the mid-90s were incited by sore memories of that War on the Shore, their wins in the early years of 21st century very definitely stoked by their outrage following the conclusion to the 1999 match at Brookline.
And then twice in the Solheim Cup, golfers have not so much shot themselves and their team-mates in the foot, as taken a blunderbuss to them.
At Loch Lomond in 2000 Annika Sorenstam holed a chip from off the green before her opponents Kelly Robbins and Hurst demanded she re-take it because it was played out of turn.
Europe was already leading, which, of course, prompted the desperate act of brinksmanship, but the home team was also vulnerable in the singles.
Not this time.
The Europeans in the team room that weekend still talk of the livid feelings which coursed through their veins after Sorenstam was reduced to tears: that juice demanded they do nothing thereafter but seize compensation in the form of victory.
Fifteen years later Suzann Pettersen's mistake in Germany was not addressing the issue of Alison Lee's latest dozy assumption of a gimme - it was that in being so intransigent about claiming the hole she granted a down-and-out American team a glimmer of hope which they were savvy enough to grasp.
She won the battle on the 17th green, but gifted America the desire to win the war.
And so to the latest continental controversy - to the awarding of the 13th hole to Nelly Korda and Ally Ewing after Korda's putt stayed up, but opponent Madelene Sagstrom picked up the ball to concede the birdie before 10 seconds had passed.
Had the ball been two feet from the hole, no issue.
It was, however, close. How close? This close:
It was maybe not quite chipgate or gimmegate, but take a look at Sagstrom's reaction. Then imagine being one of her team-mates and what all this will do to your desire to win.
Ask yourself also, what this sort of thing does to the other team. In that first video Ewing looks awkward, as did Korda through the conclusion of the match.
Neither was responsible for the mess, but nor did they do anything to take the heat out of it.
That awkwardness won't be going away on the second morning.
Unless the Americans have the hide of a rhino - or, do be more Solheim-specific, the hide of Dottie Pepper - they will be feeling sheepish.
The third option is that they flip the situation and feel wronged that the world is looking on so aghast.
Even so, their task is huge as it is.
The real story of the first day was that the European, rated rank outsiders at the start of the match, were magnificent on day one and take a 5.5-2.5 lead into the Sunday morning foursomes.
Let's take a closer look at the state of play.
Day One leaders
In the 16 match history of the Cup the leaders after day one have a very strong record.
On one occasion the match was tied at this point, but in the other 15 there were only three instances of teams turning the scoreline on its head.
The flipside of that is that the Americans are the only side to have completed a comeback - all three were theirs.
In the preview we suggested backing Europe and then laying - they are now odds-on.
Day Two foursomes
We also tipped the European to win the first morning foursomes and they did us proud.
What of the next set?
Danielle Kang and Austin Ernst versus Georgia Hall and Madelene Sagstrom
Hall has now played five foursomes, won four and earned a half in the other. She's split from Boutier, but gets to reintroduce Sagstrom to the fray. It suggests Matthew has faith in her calm authority. Kang has won just once in her last five foursomes/fourball matches.
Lexi Thompson and Brittany Altomare versus Charley Hull and Emily Pedersen
Thompson's woes in this event continue. She entered the week with a 5-4-6 record that was 1-4-4 if you took her matches with Cristie Kerr out of the equation. After two defeats on Saturday that record is now an astounding 1-6-4 (or three points from 11). Hull's foursomes record is played six, won five, halved one. Altomare putted well again on Saturday, Pedersen (in union with Hull) claimed her first point after her tough debut four years ago.
Nelly Korda and Ally Ewing versus Mel Reid and Leona Maguire
Korda faces her nemesis on the first morning: the Anglo-Irish veteran-rookie double act of Reid and Maguire. The latter was superb all Saturday. A fascinating duel and Reid, who carries off a neat cowboy's narrowed eyes and hands-on-hips combo, is likely to be motivated.
Lizette Salas and Jennifer Kupcho versus Anna Nordqvist and Mathilda Castren
America's other winning partnership get a second go, but will face a Scandinavian team that won 1-up and 4&3 on Saturday.
Every pairing is available at evens or better and plenty will appeal.
I'm a little wary of Thompson's on-going frailty - surely she must come good sooner or later? But allied with Hull's continuing excellence in the format, getting odds against for a European win in the second match is the pick.