In the opening stages Saints were understandably ring rusty. Many of the combinations hadn't played together before and, for all the training and conditioning of the past two months, nothing quite beats actually getting your hands on the ball in a match situation.
For Zebre, on the other hand, this was their third match of their pre-season campaign, and while there were bright signs for the Saints - notably eye-catching runs from Jamie Elliott and Luther Burrell - the Italians' game awareness showed when fly half Luciano Orquera chased his own kick to score the opening try.
Orquera added first the conversion and then a penalty, but not before Saints got on the scoresheet themselves through a Martin Roberts try, converted by Ryan Lamb.
However Zebre finished the first quarter on a high, forcing Ross McMillan to kill the ball and get sent to the sin bin, and then adding three more points from Orquera's right boot.
However Saints belied the disadvantage in personnel up front to score a pushover try to take the lead - Burrell the beneficiary of the forwards' grunt - before extending the advantage three minutes later through Elliott.
It was a lovely try featuring great hands from Soane Tonga'uiha and Dylan Hartley, and with Lamb's two conversions Saints had a 21-13 lead going into the break.
However the same problems beset the Saints at the start of the second half as in the first. Virtually the whole team was changed, and while they got themselves into a great position from a scrum penalty an overthrown lineout was scooped up by the Italians.
Seventy metres later this initial break became a try for full back Sinoti Sinoti. Orquera's missed conversion kept the margin to three, but while this try was the fillip the Italians wanted Saints' reply through Scott Armstrong four minutes later increased the black, green and gold advantage to 10 points.
The next 20 minutes saw plenty of endeavour and no small amount of sweat, but precious few chances for either team. There were some nice touches, however, Sinotti looking dangerous at the back for Zebre and James Wilson making plenty of distance with his kicking from inside centre.
With 10 minutes to go the deadlock was broken by Zebre wing Giovanbattista Venditti, who cantered home with plenty of support still available. But while Saints tried to up the pace once again the momentum remained with the Italians, Samuele Pace scoring in the left corner.
Orquera calmly slotted the conversion, and while Saints tried one last time the ball was turned over and Italian celebrations greeted the final whistle.
2mins ZEBRE Try Orquera Con Orquera 7-0
14mins SAINTS Try Roberts Con Lamb 7-7
18mins ZEBRE Pen Orquera 10-7
20mins SAINTS Yellow card McMillan
20mins ZEBRE Pen Orquera 13-7
28mins SAINTS Try Burrell Con Lamb 13-14
31mins SAINTS Try Elliott Con Lamb 13-21
HALF-TIME ZEBRE 13 SAINTS 21
42mins ZEBRE Try Sinoti 18-21
46mins SAINTS Try Armstrong Con Myler 18-28
50mins ZEBRE Miss pen Orquera
69mins ZEBRE Try Venditti 23-28
78mins ZEBRE Try Pace Con Orqeura 30-28
FUL-TIME ZEBRE 30 SAINTS 28