Marquez topped the 45-minute session with a time of 1m46.121s, which put him 0.087s ahead of Quartararo and 0.104s clear of KTM’s Brad Binder, as three different manufacturers finished inside the top three.
It was Ducati wildcard Michele Pirro that headed the timesheets early on, lapping the circuit in 1m47.905s in the first five minutes of the session before improving to a 1m46.917s to set a new benchmark for the remainder of the field.
Marquez then lowered Pirro’s benchmark to a 1m46.852s, with Pramac’s Jorge Martin moving up to third behind Pirro to establish a 1-2-3 for Ducati at the head of the pack.
The status quo was maintained until the final 12 minutes of the session, when Pirro moved back to the top with a 1m46.824s.
A slew of riders then enjoyed stints at the front, including Aprilia’s Maverick Vinales, LCR Honda’s Alex Rins and Quartararo as lap times tumbled in the final part of the session, before the younger of the Marquez brothers asserted his authority with a 1m46.121s with just under two minutes left on the clock.
That time would remain unbeaten till the end of practice, with Quartararo also able to hold on to second in an impressive session for the Yamaha rider.
Third place went to Binder, who leapt to third late on with a time of 1m46.225s, with French GP winner Marco Bezzecchi another 0.076s adrift on the VR46 Ducati.
Pramac duo Johann Zarco and Martin ended up fifth and sixth respectively, separated by 0.026s, while Franco Morbidelli was seventh in an encouraging first practice for Yamaha.
Vinales slipped to eighth on the Aprilia by the end of the session, while Honda’s Marc Marquez was ninth-fastest with a late effort of 1m46.409s. The top 10 was completed by Raul Fernandez on the Tech3 KTM.
Despite trading times with Alex Marquez early for much of the session, Pirro was unable to keep up with the competition and slipped to 11th at the finish, just ahead of the second factory Honda of Alex Rins.
He did manage to beat the full-season works Ducati of Jack Miller, who ended up a disappointing 14th behind LCR Honda’s Takaaki Nakagami.
Aprilia’s Aleix Espargaro finished a distant 22nd out of 24 riders after a crash just after the halfway point of the session.
Espargaro had already been struggling for performance and was down in 18th on the table when he lost the front-end of his Aprilia with 20 mins to go, sliding into the gravel trap at the final turn.
The Spanish rider suffered an ankle injury in a cycling accident ahead of the weekend and appeared to be in pain after the crash, requiring external assistance to get to a safe zone.
MotoGP Italian GP FP1 results:
| Cla | Rider | Bike | Time | Gap | Interval | |
|---|---|---|---|---|---|---|
| 1 |  Alex Marquez |
 |
Ducati | 1'46.121 | ||
| 2 |  Fabio Quartararo |
 |
Yamaha | 1'46.208 | 0.087 | 0.087 |
| 3 |  Brad Binder |
 |
KTM | 1'46.225 | 0.104 | 0.017 |
| 4 |  Marco Bezzecchi |
 |
Ducati | 1'46.301 | 0.180 | 0.076 |
| 5 | Johann Zarco |
 |
Ducati | 1'46.335 | 0.214 | 0.034 |
| 6 | Jorge Martin |
 |
Ducati | 1'46.361 | 0.240 | 0.026 |
| 7 | Franco Morbidelli |
 |
Yamaha | 1'46.400 | 0.279 | 0.039 |
| 8 | Maverick Viñales |
 |
Aprilia | 1'46.404 | 0.283 | 0.004 |
| 9 | Marc Marquez |
 |
Honda | 1'46.409 | 0.288 | 0.005 |
| 10 | Raúl Fernández |
 |
Aprilia | 1'46.428 | 0.307 | 0.019 |
| 11 | Michele Pirro |
 |
Ducati | 1'46.488 | 0.367 | 0.060 |
| 12 | Alex Rins |
 |
Honda | 1'46.506 | 0.385 | 0.018 |
| 13 |  Takaaki Nakagami |
 |
Honda | 1'46.506 | 0.385 | 0.000 |
| 14 |  Jack Miller |
 |
KTM | 1'46.564 | 0.443 | 0.058 |
| 15 | Enea Bastianini |
 |
Ducati | 1'46.801 | 0.680 | 0.237 |
| 16 | Francesco Bagnaia |
 |
Ducati | 1'46.839 | 0.718 | 0.038 |
| 17 | Fabio Di Giannantonio |
 |
Ducati | 1'46.889 | 0.768 | 0.050 |
| 18 | Luca Marini |
 |
Ducati | 1'46.934 | 0.813 | 0.045 |
| 19 | Augusto Fernandez |
 |
KTM | 1'47.442 | 1.321 | 0.508 |
| 20 | Joan Mir |
 |
Honda | 1'47.614 | 1.493 | 0.172 |
| 21 |  Miguel Oliveira |
 |
Aprilia | 1'47.853 | 1.732 | 0.239 |
| 22 | Aleix Espargaro |
 |
Aprilia | 1'48.102 | 1.981 | 0.249 |
| 23 | Lorenzo Savadori |
 |
Aprilia | 1'48.165 | 2.044 | 0.063 |
| 24 |  Jonas Folger |
 |
KTM | 1'48.482 | 2.361 | 0.317 |
| View full results | ||||||
