They survived a serious scare in the 76th minute when Inigo Perez snatched the ball from Marcos Llorente and launched a 40-yard shot over the head of keeper Kiko Cassila that thumped the crossbar and came agonisingly close to crossing the line.
"We were very good in the first half but the pace changed in the second half and Levante could have scored".
Shorn of attacking stars Lionel Messi and Luis Suarez, Barca coach Ernesto Valverde also left out captain Andres Iniesta and others including goalkeeper Ter Stegen from the starting line-up for their match at Celta.
Celta Vigo have been struggling this season and they are in need of a positive run of games that would help them to move away from the relegation zone.
Real coach Zidane usually leaps to the defence of his players after negative results but he was not in a forgiving mood on Sunday.
'He's a Madrid player and he wants to finish his career here.
Chelsea held by second-tier Norwich
Chelsea pressed late on but the closest they came to a victor was when Davide Zappacosta shot narrowly wide in injury-time. Both teams will meet in a replay at Stamford Bridge to decide who goes through into the fourth round.
Freezing rain, sleet possible late Sunday
At Hood River, Ore., a 90 percent chance of rain, possibly mixed with freezing rain is forecast for Friday morning through night. A period of freezing rain or sleet is possible late Sunday into early Monday, according to the National Weather Service .
NYC, Long Island brace for winter storm
This week's storm is expected to strike New England as a classic bomb cyclone with a dramatic 50-millibar dip in a 24-hour period. Florida Governor Rick Scott on Tuesday urged residents in the northern part of his Sunshine State to prepare for the cold.
"The main thing we lacked today was we didn't play the second half", said the Frenchman, who last season guided Real to their first Liga and European Cup double since 1958.
Real stay fourth in the standings on 32 points while Barca have 48 although they have played one game more.
It seems that the imminent signing of Kepa will not reinvigorate Real Madrid fans, since he's being considered a reinforcement for the future.
Zidane added that the result was not acceptable to him or his players. The Spanish civil and football authorities have said repeatedly that Catalan secession would end the participation of the region's clubs in the Spanish League.
Bale made his first start in the league since September 20 after finally recovering from persistent muscle problems and pulled Real level after Wass's strike with a slick first-time finish before giving them the lead by knocking a pass from Isco in with his back heel.