Jorge Jesus may have lost the likes of Lazar Markovic, Ezequiel Garay and Oscar Cardozo over the close-season but Benfica showed enough quality to get up and running in Lisbon.
While the champions were given a scare early on when Manuel Jose missed a penalty, Maxi Pereira quickly helped settled any opening-day jitters shortly before the half-hour mark.
However, the hosts were made to wait until 18 minutes from time to settle to the contest when Eduardo Salvio added a second.
Ramon Cardozo was the hero for Moreirense on their return to the top flight - the Paraguayan forward scoring 10 minutes from time at Nacional to get the visitors' campaign off to an ideal start.
There was to be no such opening-day joy for Penafiel, though, as they went down 3-1 at home to Belenenses.
Ricardo Cheu's Primeira Liga newcomers suffered a nightmare start when they fell behind to an early Fabio Sturgeon goal but were level courtesy of Joao Martins' penalty 12 minutes before half-time.
However, Penafiel were made to wait for their first points of the season thanks to second-half goals from Deyverson and Miguel Rosa.
Former Portuguese champions Boavista were also given a rude awakening to life back in the top flight - going down 3-0 to Sporting Braga at the Estadio AXA in a game that saw Fabio Ervoes dismissed for the visitors.
Pedro Tiba opened the scoring after just a minute with Ruben Micael and Eder adding second-half goals for Sergio Conceicao's side.
Earlier in the day, Rio Ave came out on top against Vitoria Setubal in a feisty contest that saw three men sent off.
Diego Lopes and Marcelo got the crucial goals for Rio Ave, who had Filipe dismissed before the interval, while Zequinha and Manu were both given their marching orders late on for the visitors.
