Nico Rosberg took the chequered flag during what was an incident-packed first race of the new Formula 1 season in Australia.
It happened on lap 17 when Alonso attempted to pass Esteban Gutierrez on the run down to turn three.
Alonso's front right wheel clipped the rear of Gutierrez's Haas car, sending the former spiralling towards the barriers before eventually coming to a halt upside down.
The Spaniard limped away from the wreckage, but was later declared to have been unhurt.
It was also a disappointing race for Lewis Hamilton, who started on pole, yet ended up falling as far down as sixth after a bad start.
He did eventually work his way up to second spot, but was unable to topple his Mercedes teammate Rosberg.
1. Nico Rosberg (Mercedes)
2. Lewis Hamilton (Mercedes)
3. Sebastian Vettel (Ferrari)
4. Daniel Ricciardo (Red Bull)
5. Felipe Massa (Williams)
6. Romain Grosjean (Haas)
7. Nico Hulkenberg (Force India)
8. Valtteri Bottas (Williams)
9. Carlos Sainz (Toro Rosso)
10. Max Verstappen (Toro Ross)
11. Jolyon Palmer (Renault)
12. Kevin Magnussen (Renault)
13. Sergio Perez (Force India)
14. Jenson Button (McLaren)
15. Felipe Nasr (Sauber)
16. Pascal Wehrlein (Manor)
Did Not Finish: Marcus Ericsson (Sauber), Kimi Raikkonen (Ferrari), Rio Haryanto (Manor), Esteban Gutierrez (Haas), Fernando Alonso (McLaren), Daniel Kvyat (Red Bull)