The Blancos' 2-2 draw with city rivals Atletico gave the Catalans the incentive of being able to move to within one point of Carlo Ancelotti's side at the summit with a win.
Barca duly delivered, but it was not as comfortable as the scoreline suggested as Alexis Sanchez and Lionel Messi put them 2-0 ahead before Angel Trujillo headed past a stranded Victor Valdes to reduce the deficit.
Although Barca squandered a host of chances, they did eventually create some breathing space as experienced duo Carles Puyol and Xavi found the net in the final 10 minutes, and Busquets admitted that they were nowhere near their best.
"It was not our best game, but we're a little closer to the leader," the central midfielder told Canal Plus.
"There are good things and things we need to improve on, but we leave for our mini-break for the international fixtures in a good mood.
"We need to stop players from scoring in aerial duels, but we're not very tall. It's not our strong point."
Barca are back in action in La Liga after the midweek international break with a trip to Real Valladolid on March 8.