Following its release, "Automatic" has received mixed reviews from
music critics. While Benjamin called the song "a slow-burning, Janet Jackson-esque R&B jam that positions them as sultry sirens", Kim cited the track as a song that stand at both extremes of "innocence and sexy". Park Soo-jung from
Ten Asia praised Red Velvet's tone and restrained "sensual" vocals for standing out on the song. Cho Ji-hwan of
Weiv noted the song for succeeding in producing its own "stickiness". On another album review, while Yoo Je-sang of
Idology called the song as "a move to take a stable position", further explaining that it certainly reminds of past idols such as
S.E.S., MRJ described the song as "a little disappointing", clarifying that he didn't know what to expect from Red Velvet this time. Jung Byung-wook of
Y-Magazine described the song as "one of the risk factors that obscures one's own color", adding that it is still unknown whether the group can have a "steady concept" or has potential as a "more advanced narrative". Jacques Peterson of
Idolator ranked "Automatic" 22nd on "The 25 Best K-Pop Songs of 2015" list, calling the song a stand-out due to its "minimalist R&B beat" and "melancholy sensuality". The song also landed on
Billboards "The 25 Best Red Velvet Songs: Critic's Picks" list at number nine, and the staff highlighted it for being one of their "smoothest cuts to date". On the 13th week of March 2015, "Automatic" debuted and peaked at number 32 on South Korea's
Gaon Digital Chart. The song has since reached total sales of 71,844 digital units in South Korea, as of March 2015. Elsewhere, the song debuted and peaked at number nine on the US
Billboard World Digital Song Sales chart, making it Red Velvet's fourth entry and at the time, their lowest peak position on the chart. The ranking of the group's lowest peak was later surpassed by their 2017
SM Station single "
Rebirth", which debuted and peaked at number 25 on the World Digital Song Sales chart. == Music video ==