Yes, he did. But ROTS Palpatine is still extremely powerful. He's been collecting-and draining- artifacts and holocrons for a long time. Did he lose to Mace? Yes. For what reason though? Can we say for sure Revan would beat Mace, described as one of the greatest fighters the Jedi Order had ever produced in over twenty millenia? How can Palp's loss with Anakin's sudden arrival be luck? Luck doesn't exist in SW. Palp is described at that time as a 'great darkness in the force', an 'event horizon' and his powers are already prodigious...in my link, it describes him as the most powerful at the time of ROTS