The Borg learn the frequency of the weapons used against them and alert the rest of the hive to adapt their shields to that frequency. So Mr. Neopets is saying that the Death Star would win the battle as presented, but any inevitable further confrontation would go to the Borg.
Why would they never be able to do it again? And this sounds like 2 Borg Cubes versus one Death Star as written.
The Borg learn the frequency of the weapons used against them and alert the rest of the hive to adapt their shields to that frequency. So Mr. Neopets is saying that the Death Star would win the battle as presented, but any inevitable further confrontation would go to the Borg.