Port Vale looked eager to get off to a good start when, after three minutes, both Nathan Lowndes and Mark Innes saw goalscoring opportunities go begging.
In what became the trend for the half, Charlie Comyn-Platt took a pot at goal after 13 minutes with a 25-yard effort that zipped past Mark Goodlad's left post.
Swindon continued to push but struggled to capitalise on their long spells in possession. Comyn-Platt went closer still after half an hour when his cross-cum-shot crashed back off the crossbar.
More dismal Vale defending saw a blocked attempt by Christian Roberts fall kindly for former Crewe player Gareth Whalley, but his shot from just outside the box was held well by the goalkeeper.
Roberts caused more problems five minutes before half time when his pace carried him past Mickey Bell, but his finish was poor, scooping the ball over the crossbar from only eight yards.
The Valiants started marginally better after the break when Lowndes managed to pull the ball back for Chris Cornes, but the youngster's left-footed shot ballooned over.
Cornes almost turned provider in the 62nd minute when his left-sided corner flashed in front of George Pilkington, but he struggled to control his header, sending the ball over the crossbar.
After finally finding their feet, Vale were cut back down to size when Hameur Bouazza followed up Stefani Miglioranzi's blocked shot to score from close range in the 66th minute.
Vale somehow clawed back a goal four minutes from time when Craig James' half-cleared corner was hammered back into the box by Tony Dinning and finally headed past a sprawling Evans by Husbands.