SANTA CLARA -- Coach Kyle Shanahan said he felt last week was just the beginning.
But, as far as the chance for the 49ers to establish a winning streak, it ended rather abruptly.
“That’s why I’m extremely disappointed,” Shanahan said following the 49ers’ embarrassing 31-17 loss to the shorthanded Arizona Cardinals on Sunday at Levi's Stadium.
“I’m obviously wrong, but I’m very surprised we didn’t play well today. I thought we had a great week of practice and I thought the guys were on it in the meetings all week, and I felt energy before the game. I was caught off guard by how we played.”
The 49ers, coming off a 33-22 win against the Chicago Bears in Week 8, went up against a Cardinals team that did not have quarterback Kyler Murray or their top two wide receivers, DeAndre Hopkins and A.J. Green.
But journeyman backup quarterback Colt McCoy torched the 49ers on 22-of-26 passing for 249 yards and one touchdown.
Shanahan said he addressed the likelihood that Murray might not play on Sunday and warned against taking the Cardinals lightly.
“You guys saw how we tackled out there,” Shanahan said. “We didn’t stop the run. We didn’t stop the screens. When you give up explosive screens, that’s free yardage. It doesn’t matter who’s playing quarterback, we made it extremely easy on them.
“It was extremely disappointing. I don’t think we tackled very well. I didn’t think we had 11 guys swarming to the ball enough. We made it pretty easy on those guys.”
Shanahan expressed confidence in defensive coordinator DeMeco Ryans. He said he would “probably not” consider any change at quarterback.
Starter Jimmy Garoppolo completed 28 of 40 pass attempts for 326 yards with two touchdowns and one interception. The 49ers’ offense stalled in the first half when tight end George Kittle and wide receiver Brandon Aiyuk lost fumbles. Aiyuk’s fumble came at the Arizona 7-yard line with the 49ers trailing 14-0 early in the second quarter.
“We didn’t play very well today at all. I was really disappointed,” Shanahan said. “I thought we’d play very well. We had a good week of practice. I thought we’d improved from the week prior. Obviously, we didn’t play like that.”