Barcelona were made to work for victory over Alaves on Sunday but late goals from Luis Suarez and Lionel Messi saw them equal a club record.
Ernesto Valverde's men remain 11 points clear at the summit and their streak of 21 games unbeaten represents Barcelona's best run from the start of a LaLiga season.
Pep Guardiola's 2009-10 title-winning side won 17 and drew four over the course of their streak, but Messi's exquisite free-kick means Vlaverde's vintage have 18 victories and three draws to their name.
Messi is represented across the three best returns, with Tito Vilanova's Barca going 19 games without defeat from the outset in 2012-13.
21 - Barcelona have equaled their longest unbeaten start to a league campaign in their history (W18 D3); under Pep Guardiola in 2009/10 (W17 D4 L0). Unstoppable. pic.twitter.com/jrCVXGXuWD-- OptaJose (@OptaJose) January 28, 2018
The next entry on the list falls some way further back, with Terry Venables leading Barcelona to 15 games unbeaten in 1984-85.
Should Valverde's side avoid defeat in next weekend's derby at Espanyol, they will be out in front on their own, although their local rivals did win 1-0 Cornella-El Prat in the first leg of this month's Copa del Rey quarter-final.