Deniz Oncu stole victory from Diogo Moreira via a photo finish to take his first-ever Moto2 victory at Aragon.
Oncu and Moreira were separated by just 0.003s across the line as the Turkish rider prevailed following an audacious move on the outside line, in what was the closest-ever finish to a Moto2 race.
Moreira got the best start to the race from pole position to lead into Turn 1 ahead of Oncu and Barry Baltus.
The leading group ran close together throughout the opening stages as Oncu moved past Moreira, with Baltus following the Turkish rider through a few corners later.
Aron Canet made a strong start from the second row of the grid and pressured team-mate Baltus and Moreira, but both riders were able to keep ahead of the experienced Spaniard.
Dani Holgado looked to have made a fast start, but was overly ambitious going into Turn 12 and crashed into team-mate David Alonso, with both riders out of the race.
On the second lap of the race, Baltus assumed the lead of the race ahead of Oncu, as both riders attempted an early breakaway from Moreira and Canet.
Canet and Moreira were able to bridge the gap to the leading pair, and the Spanish rider made a move on Oncu for second place.
As the race reached half distance, Canet made a slight error which allowed Oncu and Moreira to close back in and regain their positions.
Oncu and Baltus were the ones setting the pace at the front, with the Turkish rider taking the lead at the front and breaking the all-time lap record as he attempted to break from the Belgian.
Further down the field, championship leader Manuel Gonzalez made progress from 18th on the grid, making his way up into 8th and pressuring the riders ahead to make it into the top five.
Gonzalez used his pace to move past Alonso Lopez to move into seventh as he attempted to make up the two-second gap to Filip Salac ahead.
Out front, Moreira was the rider who had the pace in the closing stages and broke the lap record that Oncu had set just laps before.
The Brazilian rider used his advantage to pass Baltus for second as the trio appeared to have sealed the podium positions ahead of the fading Canet.
The Spanish rider lost a further position as Silverstone winner Senna Agius found his way into fourth.
Going onto the final tour of the circuit, Moreira set another fastest lap of the race as he attempted to steal victory away from Oncu.
The Brazilian managed to find a way through on Oncu, but the battle would continue throughout the final lap.
Oncu set up the final run down the straight perfectly as he gained the slipstream from Moreira in front, and parked his KTM Ajo machine on the outside line on the run to the finish.
A photo finish proved Oncu ran out as the victor, taking his first ever win in the Moto2 class 0.003s ahead of Moreira.
Baltus completed the podium in third, just under two seconds behind the leading pair.
Agius took the flag in fourth after showcasing some late race pace ahead of Salac in fifth.
Canet was forced to settle for sixth over the line, with the American Racing pair of Joe Roberts and Marcos Ramirez finishing seventh and eighth respectively.
Championship leader Gonzalez lost a few positions in the final laps and came home in ninth, while Lopez completed the top 10.
Izan Guevara finished the race in 11th ahead of Albert Arenas in 12th and last year’s race winner Jake Dixon in 13th.
Ivan Ortola crossed the line in 14th, while replacement rider Daniel Munoz completed the points finishers in 15th.
