Fernando Alonso's retirement from the Canadian Grand Prix was the biggest nail yet in the coffin of McLaren's doomed relationship with Honda.
With the Spaniard running 10th and on course to claim the team's first point of the 2017 season at Circuit Gilles Villeneuve, an oil pressure issue two laps from the finish proved any optimism to be misplaced.
The partnership between the once-great McLaren team and Honda has taken a sizeable and undeniable step in the wrong direction this season.
After finishing ninth out of 10 in the constructors' standings in the first year of the deal in 2015, a more promising 2016 saw the team finish sixth.
However, Alonso has crossed the chequered flag in just one race so far this season, while team-mate Stoffel Vandoorne has managed three finishes in seven rounds.
Even Alonso's bid to escape the underperformance of his F1 car was haunted by its failings - the Honda he drove at the Indy 500 suffered engine failure 21 laps from the end.
A driver of Alonso's talent and popularity - highlighted by his venture into the stands after pulling up on Sunday - will have plenty of offers to move elsewhere and he has not ruled out a permanent switch to IndyCar as he grows increasingly frustrated.
McLaren executive director Zak Brown conceded to having "serious concerns" about the current state of affairs ahead of Sunday's race in Montreal and those worries will only have grown deeper over the weekend.
For a team who only five years ago were regularly winning grands prix, the level of disappointment at missing out on a single point is a stark indicator of just how grave the situation has become at McLaren.
"We dared to hope", said racing director Eric Boullier after the race, speaking as if his team were chasing silverware, not scraps.
"OK, what we were daring to hope for were hardly rich pickings: a solitary world championship point for Fernando, who had driven superbly all afternoon, as he's driven superbly every race-day afternoon for the past two-and-a-half years.
"But, after so much toil and heartache, even that single point would have felt like a victory.
"And then came yet another gut-wrenching failure.
"It's difficult to find the right words to express our disappointment, our frustration and, yes, our sadness. So I'll say only this: it's simply, and absolutely, not good enough."
McLaren are considering their options regarding engine suppliers for the 2018 season, and a return to Mercedes power is thought to be under consideration.
Whatever the way forward, Honda's chances of being retained are diminishing with every passing race.