Last Wednesday night, the New York Philharmonic opened its season with a superstar pianist, Evgeny Kissin. The next night, the orchestra featured another superstar pianist: Lang Lang. That concert was broadcast on national television. Then they all got up fairly early the next morning and repeated that program, at 11 o’clock. Were they any worse for wear? Hard to say, exactly.

With music director Lorin Maazel, Mr. Lang began the program with Chopin’s Concerto No. 1 in E minor. (This is the second – the later – of Chopin’s two piano concertos, but never mind.) The piece begins with a long orchestral exposition, and Mr. Maazel took a somewhat slow tempo – or, if you like, a deliberate tempo. In either case, Mr. Maazel was unhurried, savoring the music. He could not help indulging in his trademark strange ritards: Sometimes it seemed as though the music would stop altogether.

When Mr. Lang came in, he was worrisome – immediately. That first arpeggio was loaded with rubato, was rhythmically bizarre. And if you can’t play your opening flourish straight, what are you going to do with the rest of the concerto? Indeed, Mr. Lang was highly personal, and sometimes mannered, in this music, although he displayed several strengths: He has an unbelievably fluid technique; he can make the keyboard sing; he knows not to pound. Really, this was a strangely subdued Chopin E-minor – gentle, retiring. This was astounding, coming from a pianist known as athletic, exuberant, uncontainable. It was almost as though he had resolved to play against type.

The concerto’s first movement could have used more spine, more boldness, more rigor. The way Mr. Lang played, he drew attention to the flabbiness of the score. It benefits from some reining in, as Arthur Rubinstein indelibly taught us. And the movement’s quick, wonderful ending wasn’t nearly diabolical enough (or interesting enough). It was practically limp and shy.

Mr. Lang’s best playing came in the slow movement, where he did some lovely singing. At one point, he looked at patrons in the first few rows as if to say, “Isn’t this beautiful?” He was right. And toward the end of this movement, he offered some of what I think of as the Lang Raindrop Effect. Though known as a supervirtuoso – a Lisztian – Mr. Lang is an excellent Impressionist, an excellent colorist, as he has proven in Debussy, and also in the music of his countryman, Tan Dun.

Chopin’s final movement – the Rondo – was, again, strangely subdued. It ought to be bright, folkish, a bit cocky. And its concluding pages can be downright raucous – joyfully raucous. Yet from Mr. Lang, they bordered on sleepy.

As I’ve said umpteen times already, strange.

On the second half of the program, Mr. Maazel conducted Mahler’s Symphony No. 1, known as the Titan. Mr. Maazel is an uneven Mahler conductor, as he is an uneven conductor across the board. Some of the greatest Mahler performances many of us have heard have come from Mr. Maazel’s baton; and he has laid some eggs.

One reason Mr. Maazel is an exciting conductor is that you never know how he will approach a work: He can be amazingly brisk and “objective” (I think of a performance of Schubert’s “Great” C-major symphony); or he can be maddeningly balky and willful. Much seems to depend on how he has gotten out of bed. In the Mahler First, he was fairly middle-of-the-road: He was not exactly self-effacing, but neither did he smother the score. You lost yourself in Mahler for long stretches. But then the conductor would say, “Hey, don’t forget about me!” (With those ritards, it’s impossible.)

A detail or two: In the third movement’s funeral march, principal double bassist Eugene Levinson was exemplary – the music was from another land, and another time. And in this same movement, Mr. Maazel made the G-major section – that heavenly inspiration – breathe its peace.

The finale was thoroughly competent, of course, but somehow lacking its pulsing joy, its titanic inevitability. Nearing the end, Mr. Maazel had his horn section stand. (They were a little rough and blunt throughout the symphony, by the way.) I felt that this was gimmicky and off-putting. My seatmate contradicted me, saying, “No, it was dramatic.” She may be right – you could take your pick. In any case, Lorin Maazel keeps you on your toes, even as he puts his horn players on their feet.