If Inter goes out to attack and keep their defensive strategy intact, they will have more advantage over Barcelona. If they choose to only defend, it will not end well for them. However, playing at home is a big advantage because most clubs do play better when they're at home. Barcelona didn't rest any of their players in their match against Valladolid, because they needed to win. Flick brought in his best men when Valladolid took the lead.
Facing Barcelona, which has a fairly aggressive style of play, is actually always quite difficult for any team. But in the first leg Inter Milan were able to hold them to a draw. So, Inter Milan should also be able to provide fierce resistance in the second leg. but Inter Milan cannot only use a defensive strategy and rely on counter attacks. because that will only give Barcelona more freedom to look for gaps in Inter Milan's defense. Inter Milan itself must be braver in attacking and of course while maintaining a good defense. Because a team like Barcelona must be faced with the same style that Barcelona itself would use. And I'm sure Barcelona will play full attack as usual.
Inter needs to show off their best defense against Barcelona. Because Barcelona's offensive line is better than Inter's. Inter's biggest chance is that they rested more in Barcelona. Barcelona also went to the league match with their main squad and the players are a bit more tired. Inter has to take every risk and win the match in Italy. If the match goes to extra time, their chances will decrease.