Eddie Howe said on Monday he would resign if he felt it was the best thing for Newcastle after a dismal run that has dropped the Magpies down to 12th in the Premier League.
Howe has twice led the club into the Champions League and ended a 70-year wait to win a domestic trophy by lifting the League Cup since taking over at St James' Park in 2021.
The 48-year-old has been linked with succeeding Thomas Tuchel as England manager and with the job as the next permanent Manchester United boss.
But Howe vowed to "work better" and "do more" after his side were booed off following a 3-2 home defeat to Brentford on Saturday.
"No, there's no doubt in my mind," he said when asked if he remains the right man to take the club forward.
"That's why I'm sat here. If there was, then I wouldn't be because, as I said, the club is the most important thing.
"I'd never put myself before the club. If I didn't think I was the correct man to take the team forward and I could give the players what they need, then I would step aside and let someone else do it."
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Newcastle's realistic hopes of Champions League football next season appear to be gone as they are now 10 points adrift of the Premier League's top five.
Howe's men were also dumped out of the League Cup by Manchester City last week amid a run of five games without a win in all competitions.
But they have the opportunity to bounce back against fellow strugglers Tottenham, who have yet to win a league game in 2026, on Tuesday.
"It's been a difficult run of games, it will continue to be a difficult run of games for us, but that's where we all need to show our strength of character, resolve, resilience and our feeling of how important this is to us," added Howe.
"That needs to show, most importantly, on the pitch."