Since his introduction three weeks ago, Lee Sinnott has steadied the ship at Vale, but a home match against a Doncaster side unbeaten in 11 games appeared to be a bridge too far for the young manager.
Valiants captain George Pilkington gave his side the perfect start as he managed to hook Paul Harsley's left sided corner back towards goal and into the top right corner of Neil Sullivan's net in the tenth minute.
But Vale looked less than comfortable after going ahead and some nervous defending almost cost them their lead when James Hayter's close-range shot forced an excellent save from Joe Anyon.
A hotly-contested half finished with Sinnott's men almost adding a second when Jason Talbot's low cross from the left was missed by on-loan youngster Marc Laird at the back post.
Doncaster were given the perfect opportunity to level the scores in the 53rd minute when James O'Connor fired a low ball across the box, but Lewis Guy somehow failed to put the ball into the net from six yards.
O'Connor and Guy linked up again six minutes later, but this time it was to better effect as Guy glanced his team-mate's cross firmly into the top right corner.
The visitors reversed the scoreline in the 68th minute and were helped by a slip from Ashley Westwood which allowed Hayter a clear run at goal that he didn't waste by sliding the ball underneath Anyon.
Westwood did his best to make up for the mistake when Harlsey's left-sided corner looped into the box, but the defender's header fell straight into the arms of the waiting goalkeeper.
As the clock ticked by Vale went in search for an equaliser and they almost found it when a half cleared corner fell to Talbot 25 yards out but his shot was tipped over the bar by Sullivan.
Richie Wellens put the game to bed and ended any hopes of a comeback nine minutes before the final whistle when another defensive error allowed him to slam the ball past Anyon.