BARCELONA, Aug 19 (Reuters) - Barcelona learned last week that a future without Lionel Messi does not have to be so bleak and they will look to build on the greater team unity that was on display in their season-opener when they visit Athletic Bilbao on Saturday in LaLiga. While the Argentine"s departure to Paris St Germain left Barca with a hole of roughly 50 goals per season and his rare ability to change a game in an instant, their dominant 4-2 win over Real Sociedad on Sunday indicated they could be stronger in other areas without being so beholden to their former captain. As Messi often reserved energy in games for his marauding runs and seldom closed down opponents, Barca could only press teams with nine players rather than 10, which often led to them conceding cheap goals or getting overrun versus the top sides. Against Sociedad at Camp Nou they pressed as an entire unit and scored their second goal thanks to high pressing from defender Eric Garcia deep in the visitors" half. Coach Ronald Koeman raved about his side"s display in their first game without Messi, calling it the best first half performance he had seen from Barca in years. "I would always prefer to have Messi in my team because he decides game on his own but we can be a better collective now," Koeman said. Sociedad coach Imanol Alguacil said Barca"s pressing game had made the difference and could help them compensate for the loss of Messi"s talismanic presence. "It"s almost the same team as always but now with 10 players pressing, and that"s where they won the first battle against us. If Barcelona can improve in that area, even without Messi, they will be capable of achieving great things," he said. Koeman is likely to field a similar lineup against Athletic and retain the front three of Memphis Depay, Antoine Griezmann and double scorer Martin Braithwaite. There is also likely to be no change in Koeman"s treatment of Philippe Coutinho, who was left out of the squad against Sociedad as Barca look for a new club for their record signing. Athletic made a less impressive start with a 0-0 draw at Elche and coronavirus restrictions mean they cannnot count on the intimidating atmosphere that has helped them beat Barca in recent years, although around 10,000 fans will be at the 55,000-capacity San Mames. Real Madrid also got off to a strong start in their first game without PSG-bound captain Sergio Ramos, winning 4-1 at Alaves. They travel to Levante on Sunday for a second consecutive away game while they wait for renovation works at their Santiago Bernabeu to be completed next month. Elsewhere, champions Atletico Madrid could welcome last season"s top scorer Luis Suarez back into the starting lineup when they host Elche on Sunday after the Uruguayan began last week"s 2-1 win at Celta Vigo on the bench. Reporting by Richard Martin; Editing by Ken Ferris Our Standards: The Thomson Reuters Trust Principles.