Michal Kucharczyk notched a second-half brace for Legia as their head coach Jan Urban started with a brand new forward pairing agasint Lodz compared to last season, while 19-year-old striker Patryk Mikita wrapped up the scoring for the title-holders.
Legia moved to the top of the Ekstraklasa standings as their four-goal victory gave them the best goal difference of any of the four winners in the opening round of the 2013/14 season.
It took Urban's team just two-and-a-half minutes to get on the scoreboard on Saturday with Miroslav Radovic getting in behind Lodz's defence to score and Legia were 2-0 up at half-time thanks to Jakub Rzezniczak's 40th-minute strike.
All three of Legia's top goal-scorers from their title-winning campaign did not start at the Pepsi Arena in Warsaw, with Danijel Ljuboja having been dumped for disciplinary reasons last season, while Vladimir Dvalishvili and Marek Saganowski were both on the bench.
Kucharczyk started up front alongside Mikita, who made his senior debut for Legia, and the former repaid Urban's faith in the opening 12 minutes of the second half.
In the 52nd minute, Kucharczyk got on the end of a left-wing cross to thump the ball past Lodz goalkeeper Maciej Mielcarz, while five minutes later the 22-year-old striker scored an almost identical goal after Mikita whipped the ball into the box.
Lodz hit back on the hour mark thanks to a long-range strike from Lukasz Staro but the visitors were unable to launch a serious comeback before Mikita added a fifth goal for Legia, heading home his maiden senior goal in the 88th minute.
Pogon Szczecin are second on the Ekstraklasa standings, two goals behind Legia, with a 2-0 triumph away to Zaglebie Lubin, while 14-time Polish league champions Wisla Krakow were held to a scoreless draw by Gornik Zabrze and last season's runners-up Lech Poznan drew 1-1 with Ruch Chorzow.
In Krakow, Damian Zbozien notched a brace as Piast Gliwice defeated Cracovia 3-2 to claim third spot and Jagiellonia Bialystok are fourth after a 1-0 victory away to Zawisza Bydgoszcz.
In other Ekstraklasa results, Lechia Gdansk drew 2-2 with Podbeskidzie and Korona Kielce played out a scoreless draw with Slask Wroclaw.