Souza scored a goal in each half as Fenerbahce secured a convincing 2-0 Europa League win over Lokomotiv Moscow.
The first leg of the last-32 tie was moved forward to Tuesday on account of Galatasaray's home match against Lazio in the competition on Thursday and they would do well to win in similar comfort to their local rivals.
Brazilian midfielder Souza was on hand to crown a convincing showing from Vitor Pereira's side, heading an 18th-minute opener before converting in the 72nd minute after a fleeting second-half rally from Lokomotiv subsided.
Lokomotiv goalkeeper Guilherme made a fine reaction save in the 12th minute when Robin van Persie flicked Volkan Sen's left-wing cross towards goal.
The opener arrived from the opposite flank six minutes later, Gokhan Gonul clipping a superb ball towards the six-yard box where an unmarked Souza nodded home.
Fenerbahce dominated the rest of the action until half-time, with Guilherme called upon to deny the impressive Nani and Sen, while Van Persie headed over.
A stinging drive from Petar Skuletic was unconvincingly saved by Fenerbahce goalkeeper Fabiano and skipper Aleksandr Samedov misjudged a header as Lokomotiv threatened a revival.
But they were kept on their toes as Van Persie almost converted Nani's flick on and marauding full-back Caner Erkin tested Guilherme.
Fenerbahce duly gave themselves breathing space as Sen mesmerised the Lokomotiv defence and teed up Caner for a first-time cross that Souza converted with a cushioned volley.
Van Persie appeared disgruntled when he was replaced by Fernandao, although the powerhouse forward made his presence felt by glancing wide in the 88th minute and forcing Guilherme to push a header against the woodwork.