Mansell mounted an early challenge and remained in touch throughout the 27-lap encounter to seal the third second place of his F3 career, with Luke Browning third.
A good jump saw the Australian draw alongside Mini into the opening corner but, on the outside, had no way through as he slotted into second.
It was a largely clean start until Charlie Wurz found the wall at Portier, drawing the Safety Car before the end of the opening lap.
The order stood Mimi from Mansell, Browning and Arvid Lindblad, while Aussie Tommy Smith was 17th.
That lasted only a lap before the field was racing once more.
Mansell immediately challenged Mini for the lead but again could find no way through.
They slowly eased away from the pack behind, Browning in third 2.6s off the lead after six laps.
That continued to grow, with Mini also extending a small gap to Mansell by the time they started Lap 8, with just over a second split the front two.
Mansell responded, closing back inside a second as they dropped Browning in third by the time they started Lap 9.
It was nip and tuck between the front two as they remained within a second of each other, but pulling further clear of Browning.
At the halfway point, the Williams junior had slipped back to 4.4s off the race lead, and 1.2s clear of Lindblad in fourth.
Mini finally broke clear of Mansell after 16 laps, inching out to a 1.4s advantage, the largest gap he’d had at any point to that stage.
The Australian was dropping back by a tenth of a second per lap, while Browning in third had lifted his pace and slowly began reeling in the ART entry ahead.
A three-car collision at Mirabeau saw the Safety Car called on Lap 21.
Nikola Tsolov had attempted to send it up the inside of Noel Leon into the right-hander, making contact as they skated to the outside fence.
Both were able to get going, though not before Sami Meguetounif also got involved as he arrived on the scene.
Racing was back underway as the pack began Lap 23, Mini holding a 0.4s advantage over Mansell, who was 0.5s clear of Browning.
In the chaos, Smith had kept out of trouble and risen to 13th, with 28 cars remaining in the race.
A hefty crash for van Hoepen – one of Mansell’s ART team-mates – at Tabac quickly saw the Safety Car emerge once again.
The Dutchman had been running 10th prior to the crash, which left the rear of the car with heavy damage and the circuit littered with debris from both the car and the barrier.
Officials did well to ensure a final lap of racing, Mini holding on to win from Mansell and Browning, with Smith 12th at the chequered flag.
Pos | Num | Driver | Diff |
1 | 2 | MINI | 27 laps |
2 | 23 | MANSELL | 0.8 |
3 | 14 | BROWNING | 1.7 |
4 | 3 | LINDBLAD | 2.1 |
5 | 4 | FORNAROLI | 2.6 |
6 | 1 | BEGANOVIC | 3 |
7 | 12 | BOYA | 4.8 |
8 | 7 | TRAMNITZ | 5.2 |
9 | 31 | LOAKE | 6.6 |
10 | 10 | GOETHE | 8 |
11 | 8 | SZTUKA | 8.4 |
12 | 22 | SMITH | 8.9 |
13 | 29 | VOISIN | 9.3 |
14 | 6 | RAMOS | 10.9 |
15 | 11 | MONTOYA | 11.3 |
16 | 9 | DUNNE | 12 |
17 | 18 | ESTERSON | 12.4 |
18 | 26 | INTHRAPHUVASAK | 13.4 |
19 | 21 | FLOERSCH | 13.6 |
20 | 28 | DUFEK | 14 |
21 | 16 | SHIELDS | 15.2 |
22 | 19 | HEDLEY | 15.9 |
23 | 20 | LEON | 17.3 |
24 | 27 | BEDRIN | 17.5 |
25 | 30 | WISNICKI | 20.6 |
26 | 15 | STENSHORNE | 26.4 |
27 | 25 | TSOLOV | 28.5 |
24 | VAN HOEPEN | 5L | |
5 | MEGUETOUNIF | 8L | |
17 | WURZ |