NEW YORK (AP) — The audience boost that the London Olympics provided for NBC's "Today" show in its ratings battle with ABC's "Good Morning America" was short-lived.

The Nielsen Co. said Monday that "GMA" beat "Today" in the ratings last week, the week after the Olympics concluded, by an average margin of 162,000 viewers. NBC was counting on the Olympics to provide a launching pad for its new anchor team of Matt Lauer and Savannah Guthrie, and it organized a series of concerts and visits by Olympians last week to keep up the momentum.

The week started well. NBC's audience of 4.54 million on Monday was bigger than any morning show last week, and "Today" beat "Good Morning America" by 338,000 viewers.

But "GMA" won the next four days even while not at full strength — Robin Roberts returned this Monday — and by a peak of 517,000 viewers on Wednesday, Nielsen said.

During the Olympics, "Today" dominated. It beat "GMA" each week by more than a million and a half viewers, taking advantage of its access to Olympians. The ratings after the Olympic flame was extinguished indicate that many of those viewers are not morning show regulars and retreated to their old habits.

"GMA" had beaten "Today" during each of the five weeks before the Olympics. There should be intense competition for viewers this fall; status as the top morning news show can means tens of millions of dollars in extra advertising revenue for their networks.

Roberts returned Monday after being off for two weeks, partly because of exhaustion brought on by her medical condition. Roberts has MDS, a blood and bone marrow disease once known as preleukemia. She is expected to be off for an extended period this fall after undergoing a bone marrow transplant.