This was during the fight with Haku, the first time Sasuke's Sharingan showed up in season 1. As you can see, his right eye has two black dots and the left has one.
Kakashi's eye has three dots and this was during a battle with Zabuza, the same season a few episodes earlier before Sasuke's Sharingan showed up when fighting with Haku.
What are the dots inside the eyes when someone uses Sharingan?
These dots are called tomoe.
When first awakened, each Sharingan usually will have only one tomoe (巴). Through training and continued use, the Sharingan will develop a second tomoe and then, upon full maturation, a third. All the Sharingan's abilities are available to the user from its earliest stage, but with greater development comes greater proficiency with those abilities.
For example during their first fight in the Valley of the End Sasuke was able to easily see Narutos movements after obtaining the third tomoe in one of his eyes, when he couldn't dodge them at all earlier.
