Germany won their first match against Portugal 4-0 but have since drawn with Ghana and eked out narrow wins over the US and Algeria. (Agencies)
Speaking on the eve of his team's quarterfinal clash with France at Rio's Maracana Stadium, Loew said he was still striving to find the best formula for his side.
"We have not yet delivered our best possible performance, but I don't think anyone has reached their absolute top performance yet," Loew said.
"It's not a computer game that is easily figured out. You can't easily figure out your opponent and it's not easy to programme your own team. Mistakes are made. And then there are other elements beyond the pitch,” he added.
Among those elements is a flu epidemic that has swept through his squad. At least seven players have been affected by the bug, including defender Mats Hummels, who was reportedly bed-ridden for three days.
"One third of our squad has been complaining about a sore throat," Loew said.
"But Wednesday and Thursday all players have been training and none were feeling exhaustion. I just hope that stays stable until Friday,” he added.
Germany won their first match against Portugal 4-0 but have since drawn with Ghana and eked out narrow wins over the US and Algeria.