Brighton made it back-to-back victories on Tuesday night to go top of the Championship.
Chris Hughton's side took the lead after 23 minutes through Anthony Knockaert, and then doubled their lead three minutes later when Glenn Murray converted Leroy Rosenior's cross to score his third goal of the season.
It was 3-0 in the 58th minute as Tomer Hemed scored from the penalty spot after Murray was fouled in the box. The Israeli forward notched 16 goals last season, and opened his account for this season from 12 yards.
The result puts Brighton top of the league, with no goals conceded and back-to-back 3-0 victories at home.
Defeat for Alan Stubbs' Rotherham sees them drop 21st place, one position above the relegation zone.
The Seagulls' next game is away to Reading on Saturday, where they will look to continue their early form after suffering heartbreak last season in their quest for promotion.
Having gone top of the league, Brighton fans took to Twitter to react to their win over Rotherham.
Great performance again from us tonight. 4 games played no goals conceded. With no recognised centre back apart from Lewis dunk. #bhafc— Kevin Ticehurst (@Brightonfan) August 16, 2016
Knockeart is the best player in the Championship. Fact. #BHAFC— Tom Mahoney (@Tom_Mahoney_) August 16, 2016
Ahhh that was a good solid performance from #bhafc tonight. Top of the league!— JBizzleBeard (@JBizzleBeard) August 16, 2016
If you have not seen this team play get along to the Amex quick. One of the best sides in my 58 yrs watching the Albion. #bhafc— Keith Nieland (@KeithNieland) August 16, 2016