The Black Cats beat Wycombe 2-0 in the League One play-off final to secure their return to the second tier after four seasons away.
Neil replaced Lee Johnson in February and steered Sunderland to a play-off berth before beating Sheffield Wednesday and then the Chairboys to secure promotion.
The Scottish coach knows how to succeed at Championship level, having won promotion with Norwich City and competed for a play-off place on a minimal budget at Preston North End, and Reid is desperate for the North East club to give him the tools he needs to do the same at the Stadium of Light.
Speaking to Chronicle Live, the ex-Black Cats boss warned his former side to back Neil properly in the transfer window in the coming months.
He said: “It’s great that Sunderland are back in the Championship, but they have to back the manager now to get out of the Championship and back into the big league.
“Alex has done a great job over the last three months of the season, but he is going to need backing to go forward from here.
“It’s a hard league they are going into. The Championship is really, really, tough and it is getting tougher every year. Sunderland can’t rest on their laurels, they have to push on from here and get back into the big league.
“That’s what the supporters want, it’s what the players want, and I know it’s what the manager will want.”
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Reid is bang on here and his stance will likely be echoed by the majority of Sunderland supporters.
They’ll want to see Kyril Louis-Dreyfus and Kristjaan Speakman back Neil in the upcoming transfer window.
Sunderland have worked hard to get out of League One at the fourth attempt and failing to invest in the squad this summer leaves them at risk of wasting that by suffering relegation back to the third tier.
Loan signings such as Nathan Broadhead, Jack Clarke, and Callum Doyle played an important part in the club’s promotion success in 2021/22 and will need replacing ahead of the return to the Championship while more squad depth is needed after five senior players were released.