The Brit is now up to second in the title standings and is just 37 points behind Alonso in what is becoming an increasingly close battle.
"This championship has been so unpredictable. I'm so grateful we're in the fight. We have a good car and we can compete," Hamilton told BBC Sport. "The car's not necessarily the fastest, but we're as fast as our rivals.
"[The win] is great for the championship. It just shows that anything can happen. I've had some real bad races and some good ones - and I hope some more good ones are coming. We've had some great performances in the last few races but I've not picked up points in all of them so I need to improve on that area.
"It's going to be incredibly tough. Fernando let the cat out of the bag and said they've got lots of updates coming to the next race [in Singapore]. I'm going to go back to the factory and hope that the guys are doing the same - I trust they will be. There are seven more races to go so this is just one step."
The next race is the Singapore Grand Prix which takes place on September 23.