Evans watched his side make a bright start to the match but eventually their grip on the game faded after falling behind, and he gave his reaction having slept on the defeat.
He said to themillers.co.uk: "There is no doubt we started the game exceptionally well, perhaps as good as we have played this season. We created chance after chance, hit the underside of the crossbar and it could all have been a very different story but goals change and win football matches.
"Swindon score with a great free-kick and then have a very lucky deflection right on half-time, it was a very unjust scoreline at the break. However, despite the two second-half goals being offside it was a performance that was not acceptable. We lacked the key ingredients to have a chance in any football match, desire, passion, tenacity and a vast number players who got worse as the match went on. That is a performance that these players will not be pleased about and believe me everyone is hurting this morning.
"The only answer to yesterday is hard work and response. We will take this on the chin, feel smashed around the face, take the criticism that will come but these lads will react positively through hard graft, we apologise, but now we move on and focus on MK Dons next week."