Lewis Hamilton was dealt the first significant blow of his title romp after he was penalised three grid places for the Austrian Grand Prix.
The world champion will line up from fifth in Sunday's race at the Red Bull Ring, punished for blocking Alfa Romeo driver Kimi Raikkonen in qualifying.
Ferrari's Charles Leclerc, 21, secured pole position, with Red Bull star Max Verstappen, also 21, promoted to second. The duo will form the youngest front row in the sport's history.
For Sebastian Vettel, his torrid time of late has extended into another weekend. An engine problem prevented him from starting a lap in the shootout for pole, and the German, already 76 points Hamilton in the championship standings, will start a lowly ninth.
Mercedes' Valtteri Bottas was promoted to third, while British teenager Lando Norris, just 19, will also take advantage of Hamilton's penalty to line up a career-best fourth.
Hamilton should have been on the front row at the Red Bull Ring, but for an uncharacteristic mistake in the opening moments of qualifying.
He had just left the pits when Raikkonen, who was on a quick lap, came across the Briton's slow Mercedes at the top of the hill on the approach to Turn 3.
Hamilton saw Raikkonen at the last minute, but in attempting to get out of the fast-approaching Finn's way, instead crossed his path and thwarted his lap.
"Hamilton completely blocked me," said an angry Raikkonen on the team radio after giving Hamilton the middle finger.
Hamilton was hauled in front of the stewards. After hearing from the world champion, and reviewing video evidence, they deemed he "unnecessarily impeded" Raikkonen, throwing him down the grid.
"I totally deserved the penalty and have no problem accepting it," said Hamilton. "It was a mistake on my behalf, and I take full responsibility. It wasn't intentional."
Hamilton's Mercedes boss Toto Wolff added: "The rule book says if you impede someone, and it is clear, then you get a three-place penalty.
"It is not the driver's fault, but there is a precedent, and we have to accept that."
Hamilton's punishment has played its part in a topsy-turvy grid, providing hope of an exciting race - much-needed after last week's tedious affair in France.
Leclerc will line up from the front for the second time in his career, the power-heavy track suiting the straight-line grunt in his Ferrari. The young Monegasque will be the favourite to win his first grand prix and end Mercedes' unbeaten streak.
Norris, the teenager from Somerset, has adapted to Formula One life with staggering ease.
Here, he got the very best out of his McLaren to qualify sixth, before he was bumped up two spots after Hamilton's punishment and a five-place grid drop for Kevin Magnussen following a gearbox change on his Haas.
The rising McLaren star will have a 34-year-old five-time world champion breathing down his neck on the 300-metre charge to the opening corner.
But an unfazed Norris said: "It won't be any different starting ahead of Lewis. He is just another guy I have to beat.
"At the end of the day, he will get past because he has a quicker car. The aim, however, is to keep him behind."
Norris's fellow novice George Russell beat Robert Kubica in the sister Williams to extend his qualifying record over the Pole to a remarkable 9-0.
But the 21-year-old Englishman will start from the back of the pack, like Hamilton, penalised three places for blocking another driver, this time the Toro Rosso of Daniil Kvyat.