There was no significant attempt to portray Luther as the Antichrist. For most of the Counter-Reformation, he was dead, and other Protestant leaders were appearing all over Europe, often disagreeing with Luther. Also Luther made no personal claims and was not directly powerful in Church or State.
Well before the Reformation the theory that a Pope, the Pope, or the Papacy was or might become the Antichrist was proposed in various times and places. Rival popes at Avignon and Rome accused each other of being the Antichrist; and Wycliffe, on this if little else, agreed with them both. In the Reformation Era there was only one person or institution suspected of being the Antichrist. If the Antichrist was not to be seen in the chair of St. Peter, then he was nowhere to be seen.
An analogy may help illustrate this. Suppose it was alleged that someone in Australia today was falsely pretending to be the Queen's representative and, in some sense, standing in her place, and that many believed this. If there really is such an impostor, who could it be? The only feasible suspect is Sir Peter Cosgrove, the Governor General.
If challenged General Cosgrove would not deny making the claims, but would prove that, in fact, he really is the Queen's representative. In the same way the Counter Reformers claimed that the Pope really was the Vicar of Christ and not merely pretending to stand, in some sense, in place of God. In that case the Papacy was not the Antichrist. On the other side, the belief that the Papacy was the Antichrist was generally accepted in Protestant countries for several centuries, and enshrined in many doctrinal standards. It was the opinion of Huss, Luther, Calvin, Cranmer, Knox, Wesley and others.
The Counter-Reformers disagreed, but who did they think was the Antichrist? Two Jesuits studied all the associated prophecies both in the New Testament and in Daniel, and came up with differing conclusions. Luis de Alcazar argued all the prophecies had already been fulfilled in the early Christian centuries. Francisco Ribera, while agreeing some had, concluded most would be fulfilled in the last few years before Christ's Return. Ribera taught the Antichrist, a very nasty man indeed, would base himself in Jerusalem. Ribera's Antichrist is the basis for the Antichrist of a certain genre of modern fiction, but this was not the Reformer's understanding.
So no, Luther was not accused of being the Antichrist. The Antichrist was either in the past or future, according to the Counter-Reformation. Any false teacher however can be considered an antichrist so it is likely his oponents may have said that.