In signing Germany's Lothar Matthaus, the MetroStars and Major League Soccer gained a star of the first light. And at his first news conference as a member of the MetroStars in midtown Manhattan yesterday, everyone seemed to bask in his glow. His introduction resembled the fanfare generated by Pele and Franz Beckenbauer of the Cosmos two decades ago. Television cameramen and still photographers jostled for position, a crush of reporters asked questions in several languages and even the food was up to Cosmos' vintage.

Matthaus comes with the mandate of helping to establish professional soccer in this country, a challenge he accepts enthusiastically. ''I don't feel one player alone can make a difference,'' he said yesterday. ''But together with a new commitment, we will be able to turn this around and accomplish as much success as I have accomplished in my 20 years.''

Both Pele and Beckenbauer said basically the same thing when they came to play with the Cosmos. The comparisons to the superstars that preceded Matthaus onto the New York stage only begin here.

Like Pele and Beckenbauer, who came to the United States from Brazil and Germany in the latter stages of legendary careers, Matthaus will make his MetroStars debut at Giants Stadium this spring at age 39. Like Pele and Beckenbauer, Matthaus plays soccer with the vigor and exuberance of a teenager and can accelerate as well as he did nine years ago, when he captained Germany to the World Cup triumph in the 1990 World Cup in Italy.

Like Pele and Beckenbauer, Matthaus answers all questions with ebullience and eye contact. And the 5-foot-8-inch, 155-pound Matthaus has lost little, if any, of his physical gifts at this stage of his career. He was named the player of the year last season in the Bundesliga, one of the strongest and most demanding leagues in the world.

''The main things is that I'm having fun,'' Matthaus said simply when asked how he had been able to maintain his remarkable level of performance. ''The attitude I have is that soccer is my hobby, not a job. If you have that attitude, you can succeed at any age.''

Matthaus has enjoyed success throughout his career, which started in the Bundesliga with Borussia Moenchengladbach 21 years ago. He moved to Bayern Munich in 1984 and played four seasons there before going to Inter Milan for four years, leading Inter to the Italian championship in 1989.

Matthaus returned to Germany in 1992 and has played with Bayern Munich since. Bayern's current president is none other than Beckenbauer, the man they called Kaiser in Germany. Like Beckenbauer did two decades ago for Bayern, Matthaus helped Bayern Munich capture its 15th German title and reach the European Champions' League final last season.

Perhaps the biggest triumph for Matthaus was in 1990 in the World Cup in Italy, where he captained Germany to its third World Cup victory. Beckenbauer, who was the captain of West Germany in 1974 in West Germany's second World Cup triumph -- the first came in 1954 -- was the coach of Germany in 1990.

Matthaus would like to follow Beckenbauer's steps in the United States. Beckenbauer came to the Cosmos from Bayern Munich in 1977 and, with a great deal of help from Pele, led the Cosmos to the championship that year.

Unlike Pele and Beckenbauer, who lived on Manhattan's East Side, Matthaus prefers the West Side for the simple reason that ''it's closer to New Jersey,'' he said with a laugh, ''and that's where I work.''

Matthaus was followed by about 40 European journalists on his trip to New York. He will be returning to Munich this morning. He said the thing he disliked the most about New York City was the traffic. The thing he liked the most, Matthaus said, was that he went around asking people if they knew the name Lothar Matthaus and they said no.

It is doubtful that his name would go unidentified in most of the rest of the world. Matthaus, after all, is the only field player in the world to have played in five World Cups, the other being Mexico's legendary goalkeeper Antonio Carbajal. He has played 142 games for Germany and has been named player of the year twice in his native country and world player of the year once, in 1991.