The Campos Racing driver led from the off, and despite a brief challenge from second-place starter Taylor Barnard at Turn 1, was largely unbothered from there.
The safety car was deployed on lap three after Luke Browning's Hitech-run car came to a stop on track, but Marti got the jump on the restart to maintain the lead.
MP Motorsport's Franco Colapinto passed Jenzer driver Barnard for second on lap 11 with the help of DRS, with Dino Beganovic repeating the move the following tour to take the final podium spot for Prema.
The win marks Marti's second in as many weekends, this time at both his and his team's home event, and was greeted at the podium by compatriot Fernando Alonso, whose A14 Management Marti belongs to.
He got the jump off Barnard at the line, and though the Jenzer driver made a challenge at Turn 1, he ran wide and was forced to drive around the bollard as he rejoined, with Marti holding the lead.
Browning and Leonardo Fornaroli (Trident) tussled at Turn 4 as Saturday's second-place finisher hoped to make up positions, but the pair ran wide onto the gravel.
Browning rejoined but was forced to stop with a broken suspension, prompting a yellow flag in sector two, with Fornaroli also managing to carry on.
The safety car was deployed as a result, pausing the action for three laps before racing resumed on lap six, with Marti leading the pack off early.
Barnard had looked to close on the leader by lap nine with DRS, but he then began to struggle.
The yellow flags were waved again the following lap as Hunter Yeany and Rafael Villagomez came together at Turn 2, the Rodin Carlin driver forced wide before bouncing across the kerbs and making contact with his VAR rival.
Yeany got going again but headed back to the pits to retire, avoiding another safety car.
Colapinto took second on lap 11 on the start-finish straight, taking the position from Barnard with ease, before Beganovic did the same as Barnard struggled for pace.
Gabriele Mini, who was second in the standings ahead of the race, had made up seven places by lap 13, but then had a tussle with Christian Mansell at Turn 1, failing to go around the bollard and receiving a five-second penalty.
Championship leader Gabriel Bortoleto (Trident) passed Barnard on lap 17, with Paul Aron following him through in his Prema-run car.
Mari Boya (MP) and Hitech's Sebastian Montoya also joined the fight the following tour, but Barnard was able to hold on to seventh as Boya took sixth and Montoya settled for eighth.
Gregoire Saucy, who was behind the pack, suffered a puncture as he attempted to pass Oliver Goethe for 12th, with the Trident driver's front wing clipping the rear left of the ART and ending his race. Goethe was handed a 10-second penalty for the incident.
By lap 21, Marti was two seconds ahead of Colapinto, with a further 6.5s back to Beganovic, and that gap only grew, with Marti crossing the line 4.4s ahead of the Williams junior.
Bortoleto finished fourth, with Aron and Boya in fifth and sixth. Montoya, O'Sullivan, Barnard and Goethe rounded off the top 10.
| Cla | Driver | Team | Gap |
|---|---|---|---|
| 1 | Pepe Martí |  Campos Racing |
|
| 2 |
 Franco Colapinto |
 MP Motorsport |
4.400 |
| 3 | Dino Beganovic |  Prema Powerteam |
10.400 |
| 4 | Gabriel Bortoleto | Trident |
13.400 |
| 5 | Paul Aron | Prema Powerteam |
14.100 |
| 6 | Mari Boya | MP Motorsport |
19.500 |
| 7 |
 Sebastian Montoya |
Hitech Pulse-Eight | 19.800 |
| 8 |
 Zak O'Sullivan |
Prema Powerteam |
23.700 |
| 9 | Taylor Barnard |  Jenzer Motorsport |
25.000 |
| 10 | Christian Mansell | Campos Racing |
26.100 |
| 11 | Nikita Bedrin | Jenzer Motorsport |
27.900 |
| 12 |
 Caio Collet |
Van Amersfoort Racing |
28.300 |
| 13 | Hugh Barter | Campos Racing |
31.900 |
| 14 | Gabriele Minì | Hitech Pulse-Eight | 32.300 |
| 15 |
Jonny Edgar |
MP Motorsport |
34.200 |
| 16 | Oliver Goethe | Trident |
35.800 |
| 17 |
 Kaylen Frederick |
 ART Grand Prix |
37.800 |
| 18 | Oliver Gray | Rodin Carlin | 39.200 |
| 19 | Nikola Tsolov | ART Grand Prix |
39.700 |
| 20 |
 Sophia Flörsch |
PHM Racing by Charouz | 40.300 |
| 21 | Piotr Wiśnicki | PHM Racing by Charouz | 41.000 |
| 22 | Alex Garcia | Jenzer Motorsport |
44.400 |
| 23 | Tommy Smith | Van Amersfoort Racing |
47.600 |
| 24 | Roberto Faria | PHM Racing by Charouz | 52.300 |
| 25 |
 Rafael Villagomez |
Van Amersfoort Racing |
58.000 |
| 26 |
 Ido Cohen |
Rodin Carlin | 59.000 |
| 27 |
Gregoire Saucy |
ART Grand Prix |
|
| Leonardo Fornaroli | Trident |
||
| Hunter Yeany | Rodin Carlin | ||
| Luke Browning | Hitech Pulse-Eight | ||
| View full results | |||
