The Germans lost their opening game 1-0 to France with defender Mats Hummels putting through his own net in the first half. It was a hugely disappointing attacking performance from Löw's side who tested French keeper Hugo Lloris just once over the course of the 90 minutes.
Group F is very much a 'Group of Death' and with Portugal and France having three-point advantages on Germany, defeat this afternoon could all-but-confirm their early exit from the tournament.
Germany must be more intense in attack
Speaking in Germany's pre-match press conference, the message from Löw was clear, his side simply must show a lot more in attack against Portugal than they did against France.
He said "Tactically, we have to add something to our game in attack, more offensive power, more attacking power. After analysing our last match, I also saw that we have to get better at getting out of dangerous spaces, get positioned and set up well.
"The match against France showed that we need to be more intense, more effective in our positioning and this is a little change that we will make.
"In defending, we were set up well, we were organised, there aren't so many tactical tweaks that are necessary."
Standards are set very high
Löw went on to emphasise the high standards that he has set his side going into the Portugal game. Each player has been set specific tasks which they are expected to carry out to a very high standard to give Germany the best possible chance of winning the game.
"All of the players who walk onto the pitch will need to be ready to take on certain tasks;" Löw said. "Of course, they have their own personalities and identities but in each position, we know what we expect."
Portugal are at the top of their game
Germany's latest opponents Portugal won their first European title in 2016 and Löw believes that his side are coming up against a team who have bonded well and are in a very good place.
He said "Portugal have been at the top level for four or five years with winning the EURO title. They grew together, they are a great team, very balanced and they have top individual players. They defend very well, they are as strong as France, particularly in the air.
"I can tell you that they have top class players, not just Cristiano Ronaldo but four or five more who can all score goals. They use combination plays, they are technically very strong and they are a real threat."
Germany's latest Group F fixture against Portugal in Munich kicks-off at 5pm this evening.