Rafael Benitez refused to guarantee his future at Newcastle United as he reminded the club strengthening would be needed on their return to the Premier League.
The Spaniard's side celebrated a return to the top flight on Monday with a 4-1 win at home to Preston North End guaranteeing promotion from the Championship.
Benitez, who signed a three-year deal in May last year, said he was unsure what his future held as he hinted he would need significant transfer backing to ensure Newcastle were competitive next season.
"You never know, that is football," he said when asked about his future.
"I am really pleased to be here, and really happy and proud for everything we have achieved.
"Hopefully we can put in the foundations for something that will be a guarantee for the future. The fans have been amazing with me, their loyalty means everything.
"Having this city behind you means everything. They should have a top team. That is why I decided to stay, and now I am even happier than before that I made this decision. I am really proud and really pleased.
"Now is the time to enjoy what we have done. But then I must make sure we do the right things.
"We have to prepare everything to be strong enough for the Premier League."
A brace from Ayoze Perez and goals from Christian Atsu and Matt Ritchie saw Newcastle to their 27th win in 44 league games this season.
Benitez, whose team sit second to Brighton and Hove Albion, was delighted with the hard work done by his side.
"It feels really good. I'm really proud of everyone because we knew it would be difficult at the beginning, when everyone was saying, 'Rafa has no experience of the Championship and it will be tough'," he said.
"They were right, it was very difficult, but the commitment and hard work of the players every day, and the staff and everyone involved, and then the support of the fans, has made a massive difference.
"It is a day we have to remember because it is not easy to go down, and then come straight back up first time."