advice please

Took Alfie out today on his usual walk to the local field, whilst on route to the field came accross another staff off lead with owner in pursuit calling the dog back, the dog had escped from the house and was paying no attention to its owner. Sure enough he saw Alfie and came rushing over, Alfie has no issues with other dogs and plays happily with other dogs in the field.
The other dog immediately went for Alfie and a fight ensued, by now the other dogs owner had caught up and between us we eventually managed to seperate them, Alfie came out of it unscathed but the other dog was qite badly injured; my main concern is will this effect Alfie with other dogs

Honestly, its hard to say but the best thing you can do is not to be anxious around other dogs or Alfie will pick up on it   

Ah what a nightmare! How old is Alfie now?

He's 20 months

Okay, so his socialization period is out of the way, that's good! As long as he was previously happy with dogs hopefully this won't affect too much. Take it slow, make sure his next few interactions are relaxed and positive and as Saz has said, stay calm yourself If he is a little unsure for a while, don't panic!

This could affect him possibly, but then again it may not,,from experience with my sisters rottie,i know its a different dog,he loved to play with other dogs,one day a dog snapped at him in the face,and since then she has to lead him all the time,he goes beserk if a dog goes near him or barks..hope for you this is not the case and glad your dog was not hurt x

Hopefully he won't be affected, can't add too above advice just take it easy

UPDATE
Took Alfie for his normal run in the field yesterday, little bit anxious about what would happen when we came accross other dogs, although tried not to let on to Alf. There weren' t many dogs in the field yesterday and those that were was out of range, untill out of the blue a friendly collie appeared probably good that it sneeked up on us, I didnt get chance to show any anxiety, he ran up to Alf who thank god responded in his usual way by turning and running away, then came back and they both played happily. Such a relief that Alfie hasn't been affected by the incident on Monday

That's good to hear, I have had this happen with Vin on several occasions but it hasn't affected his behaviour at all towards other dogs.   

So glad everything's fine   

Great to hear that Alfie is OK now,