Was it an expert Berserker or a regular one? If it was an expert, it should be able to eliminate a decent number of dragons in one round, especially if you position them to attack each other.
And could you provide a link?

It was an expert Berserker; I played 20 battles, and still, a couple of thousand dragons remained.
Link:
http://heroescommunity.com/viewthread.php3?TID=5431&pagenumber=2

Added after 6 hours and 5 minutes
Unfortunately, I don't have the save file. I have a save from a bit earlier, when the Phoenixes and the Grand Guardian Dragon hadn't been eliminated yet. I'm having trouble with the uploads; could you please tell me how to add an attachment?

Added after 21 minutes
In general, to all the respected participants – I want to point out that childish attempts to play with supposedly "super-heroes" – Solmyr and others – are pointless. Rushing in the first few weeks is bad. It doesn't reveal tactics and strategy. A prolonged game, in turn, eliminates the influence of supposedly "cheating" heroes. Show me Solmyr when all my skills are at 20; his chain is useless