EAST LANSING, Mich. (AP) - Michigan State earned a spot atop The Associated Press poll by beating then-top-ranked Kentucky last week.
The Spartans will have to play much better to stay No. 1 in college basketball.
Keith Appling matched a career high with 25 points to help Michigan State pull away to beat Portland 82-67 on Monday night in its first game as a top-ranked team in 13 seasons.
"I think it will be good for us in the end," Izzo said. "Nobody has to worry about us peaking in November."
The Spartans (4-0) struggled in the first half, leading by four points after seven lead changes and three ties.
Travis Trice's 3-pointer broke a tie with 12:26 left and he followed that up seconds later with a steal and layup. Gary Harris made a 3-pionter - the team's 11th from behind the arc - midway through the second half that put Michigan State ahead by 10 points for the first time.
"The big thing was our energy level," Appling said. "That's where we were lacking in the first half. Once we picked that up, everything was good."
The Pilots (1-2) were balanced on offense with Kevin Bailey leading the way with 12 points and pesky on defense and the boards. They scored the first points of the game and led twice more in the opening 4 minutes. When it looked like Michigan State might pull away early in the game, Portland proved it could stick around a little longer.
"This early in the season, I love that we're coming to a place that you know they're playing basketball a certain way and they're doing things right: selfish, tough and with passion," Portland coach Eric Reveno said. "We can take that away and know we can compete."
The Spartans were sluggish for more than a half, playing several hours after being voted No. 1 in The Associated Press' college basketball poll for the first time since they were defending champions during the 2000-01 season. The only other season in which they were atop the poll was 1978-79 when the Earvin "Magic" Johnson-led team went on to claim the NCAA championship.
"Being No. 1 doesn't mean anything - not now," Appling said. "I'm glad people respect us that much, but we've accomplished nothing."
Michigan State has had two lackluster wins since its victory over the Wildcats. The Spartans needed to close Friday night's game strong to avoid getting upset at home by Columbia and were not impressive against Portland.
"We're still a work in progress in a lot of ways," Izzo said.
Adreian Payne scored 19 points and Harris had 15 for the Spartans.
Appling matched a career high with five 3-pointers, making each of his attempts from beyond the arc. He also had seven assists and only one turnover.
"That was one of the greatest point guard performances in many, many, many years when you look at what he shot and the decisions he made," Izzo said. "He did just an unbelievable job defensively.
"He was worth the price of admission."
Even though enough people paid for tickets that it was a sellout, a lot of fans didn't bother to show up to watch the nation's top-ranked team play.
When Izzo walked onto the court about 10 minutes before tipoff, he reacted with "disappointment," when he saw a lot of empty seats in the lower level of the Breslin Center and a lot of rows near the top of the arena without students sitting or standing in them.
"It had an affect on a lot of people, including me," Izzo said.
Payne and Harris both made three 3-pointers, helping the Spartans connect on 13 3s for the first time since 2008.
"They shot a little better than we thought from 3," Portland forward Ryan Nicholas said. "But that's one thing we were going to live with."
Nicholas and Bobby Sharp had 11 points apiece for the Pilots, who had six players score at least seven points.
Michigan State was outrebounded in its previous two games, and edged Portland on the boards by just four.
"Our main focus was rebounding and stopping them in transition," Nicholas said.
After playing the Pilots of the West Coast Conference, Michigan State will face Virginia Tech on Friday night in Brooklyn, N.Y. and then Oklahoma or Seton Hall the following night. The Spartans' next marquee game will be Dec. 4 at home against No. 24 North Carolina.