"Southampton played well today and deserved to win," he told Sky Sports.
"We weren't at our best physically and weren't at our best technically, so there's a lot to learn. I sensed straightaway that we weren't at our normal level.
"Their (equalising) goal was a key moment because we had been good value for our lead. We started well and had a few chances and defensively it was a poor goal to concede."
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Although Bournemouth had a day more than their opponents to recover from a midweek game, having played Leicester on Tuesday, Howe believed the 1-0 win over the champions might have taken a lot out of his players.
"When you look back did the Leicester game take more out of us than we thought at the time?" he said.
"With three games in eight days would we have rotated the team more? All these are questions I have to think about.
"I don't need reminding how difficult this league is but the intensity levels are extreme and the players have to go through a lot.
"It's a bad day at the office for us but we have to bounce back."
One positive aspect for Howe was the performance of Nathan Ake, playing in central defence but scoring his third goal in six games.
"I thought Nathan was excellent," the manager said. "If you take away his goal he defended really well, he used the ball well and he got into some good positions.
"It's a positive from today."
(Reporting by Steve Tongue; Editing by Clare Fallon)
