Inter and Atletico Madrid geared up for 2017-18 by scoring three goals apiece in friendly wins over Villarreal and Brighton and Hove Albion respectively on Sunday.
It proved to be a mixed day for Premier League teams, with Everton and Bournemouth claiming 2-2 draws against sides with considerable European pedigree.
Newcastle United, meanwhile, saw off Hellas Verona but that victory nevertheless caused some concerns for manager Rafael Benitez.
INTER SINK YELLOW SUBMARINE, TASTY DRAW FOR NAPOLI WITH CHERRIES
Stevan Jovetic, a reported target for Sevilla and Marseille, gave Inter boss Luciano Spalletti a timely reminder of his talents with a super second-half volley in the 3-1 win over Villarreal.
The 27-year-old Montenegro international restored Inter's lead after Roberto Soldado cancelled out Eder's opener and Marcelo Brozovic - a second-half substitute like Jovetic - made sure of the win in the final minute.
Serie A counterparts Napoli needed a Piotr Zielinski equaliser five minutes from time at Premier League side Bournemouth.
Last season's top scorer Dries Mertens got the decisive touch on a Lorenzo Insigne shot to put the visitors in front after half an hour, but Bournemouth weathered the remainder of the Napoli storm before the break and were rewarded as Benik Afobe headed an equaliser from close range and captain Simon Francis notched a rare goal.
SANDRO OFF THE MARK
Sandro Ramirez scored his first goal for Everton in an entertaining 2-2 draw with Sevilla at Goodison Park.
The Spaniard slotted the opener after just 30 seconds but the Toffees still needed a late Kevin Mirallas penalty to avoid defeat.
Sevilla midfielder Ever Banega, re-signed from Inter in June, struck a double in between those two goals to steer his side away from a second loss in the space of 24 hours, the Liga outfit having gone down 2-0 to Southampton a day earlier.
TORRES ON TARGET IN ATLETI VICTORY
Brighton slipped to their first pre-season loss as Atletico Madrid pounced late on to deny the hosts with a 3-2 win at the Amex.
Lucas Hernandez's 88th-minute strike decided the contest after Nicolas Gaitan and Fernando Torres had twice given the Liga side the lead.
Pascal Gross and Steve Sidwell scored equalisers for Chris Hughton's side but it was not enough to avoid defeat in their final match before the visit of Manchester City in the first round of the domestic league season.
GAYLE BLOW AS MAGPIES EASE PAST VERONA
Aleksandar Mitrovic started up front in the absence of Dwight Gayle but it was Newcastle United's wingers who stole the show in a 2-0 win over Hellas Verona.
Ayoze Perez slotted the opener inside five minutes and Christian Atsu added a second moments later to secure a comfortable victory.
However, the inability of Mitrovic to find the target and Gayle's need to nurse a leg complaint will give Rafa Benitez some concern ahead of their opening Premier League clash at home to Tottenham.