Marc Marquez continued his relentless chase of championship leader Stefan Bradl by winning a frenetic San Marino Grand Prix at Misano. No fewer than six riders were involved in the fight for victory but the Catalunya Caixa rider prevailed to take his fifth victory in six races, closing Bradl's lead in the standings to 23 points.
Both contenders made nervous starts to the race with Bradl almost highsiding his Kalex on the exit of turn 14, releasing Marquez into the lead ahead of Scott Redding. The British teenager was on fire in the early stages and dived past Marquez at the start of lap two before the Spaniard made an error coming onto the back straight, falling behind Bradl and Andrea Iannone to fourth.
As Redding tried to gap the chasing pack, Bradl started to go backwards. Iannone deprived him of second on lap four before Marquez took third two laps later. The Kalex rider was even under pressure to hang on to fourth as Bradley Smith and Alex De Angelis closed in on the leading group.
A period of calm followed as the top six closed together but in Moto2, chaos is never too far away and it was “Crazy Joe” that sparked the race into life at half distance. Iannone dived up the inside of Redding for the lead into turn nine but only succeeded in slowing them both, allowing Marquez to sneak past on the back straight. Redding's lack of momentum proved costly as Bradl sneaked back onto third.
Iannone triggered more madness two laps later with a typically aggressive move on Marquez. Once again, the manoeuvre forced both riders wide and opened the door for Bradl and the German took second.
The polesitter took the lead for the first time on lap 17 but now had the hard-charging Iannone to deal with. Turn eight was his overtaking place again while Bradl came dangerously close to hitting the back of the Suter, falling to fourth.
Iannone was given a taste of his own medicine a lap later with Marquez hitting the front once again. The 18 year old kept his head superbly and was clearly in no mood for a dogfight as he stormed into a one second lead.
Bradl eventually made it back past Iannone for third on the penultimate lap, this time for keeps, but ran out of time in his attempts to reel in Marquez, taking the chequered flag 0.619s adrift and a tenth ahead of Iannone. Alex De Angelis got the better of the British duo to take fourth while Redding was forced to resist a final lap attack from Smith to secure fifth place.
Scott Redding put in one of his strongest performances of the year to take fifth
After starting from the front row, Yuki Takahashi's race never recovered from a mistake at turn two which cost him several places. The Japanese rider held off Thomas Luthi for seventh while Pol Espargaro snatched ninth from Simone Corsi on the line. The all-Spanish fight for 11th also went down to the wire with Esteve Rabat pipping Julian Simon.
One year on from the tragic death of Shoya Tomizawa, the Technomag-CIP team had some points to celebrate after Dominique Aegerter stormed through from 29th on the grid to 13th while Michele Pirro and Mika Kallio claimed the final points.
Race Result (26 Laps):
| Pos | Rider | Nat | Bike | Team | Time/Gap |
| 1 | Marc Marquez | SPA | Suter | Team Catalunya Caixa Repsol | 43:08.197 |
| 2 | Stefan Bradl | GER | Kalex | Viessman Kiefer Racing | +0.619 |
| 3 | Andrea Iannone | ITA | Suter | Speed Master | +0.713 |
| 4 | Alex de Angelis | RSM | Motobi | JIR Moto2 | +1.634 |
| 5 | Scott Redding | GBR | Suter | Marc VDS Racing Team | +3.275 |
| 6 | Bradley Smith | GBR | Tech 3 | Tech 3 Racing | +3.436 |
| 7 | Yuki Takahashi | JAP | Moriwaki | Gresini Racing Moto2 | +5.255 |
| 8 | Thomas Luthi | SWI | Suter | Interwetten Paddock Moto2 | +8.739 |
| 9 | Pol Espargaro | SPA | FTR | HP Tuenti Speed Up | +13.224 |
| 10 | Simone Corsi | ITA | FTR | Ioda Racing Project | +13.551 |
| 11 | Esteve Rabat | SPA | FTR | Blusens-STX | +17.533 |
| 12 | Julian Simon | SPA | Suter | Mapfre Aspar Team Moto2 | +18.163 |
| 13 | Dominique Aegerter | SWI | Suter | Technomag-CIP | +18.254 |
| 14 | Michele Pirro | ITA | Moriwaki | Gresini Racing Moto2 | +19.180 |
| 15 | Mika Kallio | FIN | Suter | Marc VDS Racing Team | +24.454 |
| 16 | Mike Di Meglio | FRA | Tech 3 | Tech 3 Racing | +24.858 |
| 17 | Mattia Pasini | ITA | FTR | Ioda Racing Project | +24.992 |
| 18 | Claudio Corti | ITA | Suter | Italtrans Racing Team | +35.358 |
| 19 | Randy Krummenacher | SWI | Kalex | GP Team Switzerland Kiefer Racing | +35.800 |
| 20 | Tomoyoshi Koyama | JAP | Suter | Technomag-CIP | +37.371 |
| 21 | Ricard Cardus | SPA | Moriwaki | QMMF Racing Team | +37.484 |
| 22 | Raffaele de Rosa | ITA | Suter | NGM Forward Racing | +47.904 |
| 23 | Kenny Noyes | USA | FTR | Avintia-STX | +48.833 |
| 24 | Santiago Hernandez | COL | FTR | SAG Team | +56.858 |
| 25 | Valentin Debise | FRA | FTR | Speed Up | +1:06.771 |
| 26 | Joan Olive | SPA | FTR | Blusens-STX | +1:07.053 |
| 27 | Anthony West | AUS | MZ-RE Honda | MZ Racing Team | +1:13.378 |
| 28 | Jacob Gagne | USA | FTR | Aeroport de Castello | +1:21.741 |
| 29 | Alessandro Andreozzi (WC) | ITA | FTR | Andreozzi Reparto Corse | +1:30.644 |
| 30 | Mashel Al Naimi | QAT | Moriwaki | QMMF Racing Team | +1 Lap |
| Not Classified | |||||
| Aleix Espargaro | SPA | Pons Kalex | Pons HP 40 | +13 Laps | |
| Max Neukirchner | GER | MZ-RE Honda | MZ Racing Team | +13 Laps | |
| Carmelo Morales | SPA | Suter | Desguaces La Torre G22 | +14 Laps | |
| Jules Cluzel | FRA | Suter | NGM Forward Racing | +20 Laps | |
| Alex Baldolini | ITA | Pons Kalex | Pons HP 40 | +26 Laps | |
| Xavier Simeon | BEL | Tech 3 | Tech 3 B | +26 Laps | |
| Robertino Pietri | VEN | Suter | Italtrans Racing Team | +26 Laps | |
| Ratthapark Wilairot | THA | FTR | Thai Honda Singha SAG | +26 Laps | |
| Jordi Torres | SPA | Suter | Mapfre Aspar Team Moto2 | +26 Laps | |
Lap Leaders: Marquez (1, 13-15, 21-26), Redding (2-12), Iannone (16, 18, 20), Bradl (17, 19)
Riders' Championship (After Round 12: San Marino)
| Pos | Rider | Nat | Bike | Team | Wins | Pts |
| 1 | Stefan Bradl | GER | Kalex | Viessman Kiefer Racing | 4 | 213 |
| 2 | Marc Marquez | SPA | Suter | Team Catalunya Caixa Repsol | 6 | 190 |
| 3 | Andrea Iannone | ITA | Suter | Speed Master | 2 | 112 |
| 4 | Alex de Angelis | RSM | Motobi | JIR Moto2 | 109 | |
| 5 | Bradley Smith | GBR | Tech 3 | Tech 3 Racing | 102 | |
| 6 | Simone Corsi | ITA | FTR | Ioda Racing Project | 99 | |
| 7 | Thomas Luthi | SWI | Suter | Interwetten Paddock Moto2 | 96 | |
| 8 | Yuki Takahashi | JAP | Moriwaki | Gresini Racing Moto2 | 71 | |
| 9 | Esteve Rabat | SPA | FTR | Blusens-STX | 67 | |
| 10 | Julian Simon | SPA | Suter | Mapfre Aspar Team Moto2 | 62 | |
| 11 | Aleix Espargaro | SPA | Pons Kalex | Pons HP 40 | 54 | |
| 12 | Randy Krummenacher | SWI | Kalex | GP Team Switzerland Kiefer Racing | 52 | |
| 13 | Dominique Aegerter | SWI | Suter | Technomag-CIP | 48 | |
| 14 | Scott Redding | GBR | Suter | Marc VDS Racing Team | 47 | |
| 15 | Kenan Sofuoglu | TUR | Suter | Technomag-CIP | 45 | |
| 16 | Michele Pirro | ITA | Moriwaki | Gresini Racing Moto2 | 45 | |
| 17 | Pol Espargaro | SPA | FTR | HP Tuenti Speed Up | 43 | |
| 18 | Jules Cluzel | FRA | Suter | NGM Forward Racing | 35 | |
| 19 | Yonny Hernandez | COL | FTR | Blusens-STX | 33 | |
| 20 | Max Neukirchner | GER | MZ-RE Honda | MZ Racing Team | 32 | |
| 21 | Mattia Pasini | ITA | FTR | Ioda Racing Project | 26 | |
| 22 | Mika Kallio | FIN | Suter | Marc VDS Racing Team | 19 | |
| 23 | Anthony West | AUS | MR-RE Honda | MZ Racing Team | 18 | |
| 24 | Alex Baldolini | ITA | Pons Kalex | Pons HP 40 | 18 | |
| 25 | Kev Coghlan | GBR | FTR | Aeroport de Castello | 11 | |
| 26 | Claudio Corti | ITA | Suter | Italtrans Racing Team | 9 | |
| 27 | Xavier Simeon | BEL | Tech 3 | Tech 3 B | 9 | |
| 28 | Mike Di Meglio | FRA | Tech 3 | Tech 3 Racing | 8 | |
| 29 | Ratthapark Wilairot | THA | FTR | Thai Honda Singha SAG | 4 | |
| 30 | Ricard Cardus | SPA | Moriwaki | QMMF Racing Team | 2 | |
| 31 | Axel Pons | SPA | Pons Kalex | Pons HP 40 | 1 |
