Brad Binder has been crowned Moto3 champion after finishing second in a thrilling Aragon race, wrapping up the lightweight class crown with four races still to run.

The Red Bull KTM Ajo rider arrived at the Spanish venue needing a second place finish to be certain of sealing the title, with a lead of 106 points over nearest rival Enea Bastianini.

And that was the position that Binder took amid a pulsating four-way battle, missing out on a sixth victory of the season by just 0.030s from the Estrella Galicia Honda of Jorge Navarro.

Bastianini and his Gresini Honda teammate Fabio di Giannantonio completed a top four split by just 0.162s.

"It doesn't feel real yet," said Binder, who becomes the first South African to win a Grand Prix motorcycle title in any class since Jon Ekerold in 1980.

"The race was tough, it came down to the final lap. I knew where I had to be and I gave it a try, but I was so terrible in the final corner.

"Today we lost the battle, but we won the war, so I'm really happy."

Binder moves up to Moto2 next season with the new Ajo-run KTM effort, where he will partner former teammate Miguel Oliveira.

Navarro wins epic four-way dice

On the penultimate lap, Binder had not been in a position to win the title as he ran fourth with rival Bastianini - who had to win to keep himself in realistic contention - leading.

The sole KTM man against three Hondas, Binder carved his way past both di Giannantonio and Navarro, only to then drop back behind both some corners later.

Repassing di Giannantonio, Binder found himself third on the critical run to the final corner, but with the advantage of a double slipstream as Navarro drafted by Bastianini.

Darting to the outside, Binder braked impossibly late and for a fleeting second looked as if he would be able to sweep around the outside of both his rivals for the win - but Navarro just tucked his Honda back underneath the KTM to seize the advantage and his second win of the year.

But second ahead of Bastianini and di Gianntonio was enough for Binder, who now has an unassailable points lead of 111 with just 100 left to play for.

Joan Mir was fifth, a further 1.5s behind the leading group, after a superb comeback from a lowly P24 on the grid, the Leopard Honda rider narrowly heading the lead Mahindra of Jorge Martin and Navarro's teammate Aron Canet.

RBA teammates Gabriel Rodrigo and Juanfran Guevara were eighth and ninth, ahead of Phillip Oettl - who ran with the leaders in the middle part of the race before dropping back to 10th late on.

Moto3 race results:

Pos	#	Rider	Bike	Time/Gap
1	9	Jorge Navarro	Honda	39'56.973
2	41	Brad Binder	KTM	0.030
3	33	Enea Bastianini	Honda	0.107
4	4	Fabio Di Giannantonio	Honda	0.162
5	36	Joan Mir	KTM	1.724
6	88	Jorge Martin	Mahindra	1.903
7	44	Aron Canet	Honda	1.979
8	19	Gabriel Rodrigo	KTM	3.008
9	58	Juan Francisco Guevara	KTM	3.101
10	65	Philipp Ottl	KTM	3.559
11	16	Andrea Migno	KTM	3.594
12	20	Fabio Quartararo	KTM	6.883
13	17	John McPhee	Peugeot	9.742
14	23	Niccolo Antonelli	Honda	9.758
15	64	Bo Bendsneyder	KTM	9.776
16	21	Francesco Bagnaia	Mahindra	9.931
17	55	Andrea Locatelli	KTM	13.358
18	11	Livio Loi	Honda	13.645
19	95	Jules Danilo	Honda	18.776
20	76	Hiroki Ono	Honda	22.193
21	24	Tatsuki Suzuki	Mahindra	22.800
22	89	Khairul Idham Pawi	Honda	30.459
23	7	Adam Norrodin	Honda	30.749
24	12	Albert Arenas	Peugeot	36.510
25	48	Lorenzo Dalla Porta	KTM	43.028
26	40	Darryn Binder	Mahindra	43.441
27	42	Marcos Ramirez	Mahindra	43.478
28	6	Maria Herrera	KTM	1'10.624
29	77	Lorenzo Petrarca	Mahindra	1'14.198
30	18	Gabriel Martinez-Abrego	Mahindra	1'45.935
NC	43	Stefano Valtulini	Mahindra	11 laps
R	8	Nicolo Bulega	KTM
R	3	Fabio Spiranelli	Mahindra
R	84	Jakub Kornfeil	Honda