Middlesbrough were indebted to goalkeeper Darren Randolph as Preston somehow settled for a Sky Bet Championship goalless draw at the Riverside.
Garry Monk's men entered the contest as favourites having won their previous three home games this campaign.
Yet it was the visitors who dominated as an off-colour Middlesbrough struggled for balance and fluidity.
Preston were the better side from the off, with a fine Randolph stop and the woodwork denying Tom Barkhuizen.
Hopes that regrouping at the interval would cure Middlesbrough's ills proved misguided as North End continued to control proceedings.
Yet a deserved winner was not forthcoming, with Randolph on hand to deny skipper Paul Huntington from six yards in the second period.
Middlesbrough 0-0 Preston North End
