Pressure was on England to deliver an improved performance and to show what they had learned in friendly matches last year where they looked defensively vulnerable and far from their best.
Several key players were missing through injury including Stanway, Lauren Hemp, Beth Mead and Alex Greenwood, but Wiegman named a strong starting XI.
Manchester United midfielder Clinton was trusted to fill the void left by midfielder Stanway and she excelled initially, switching play effectively and linking up nicely with club team-mate Ella Toone.
They combined early on when Clinton's through ball found Toone, but she dragged the ball inches wide of the far post with Russo unable to get on the end of it.
Minutes later, Bronze's brilliant delivery found Russo unmarked a few yards out and the Arsenal striker made no mistake, continuing her goalscoring form to give the Lionesses a deserved lead.
England looked much more assured in possession in the first half but once again, they allowed their opponents back into the game.
Portugal, who had showed glimpses of attacking threat with pace in wide positions during the first half, began to open the game up and capitalised on the visitors' dip.
The midfield trio of Clinton, Toone and Keira Walsh struggled to handle Nazareth when she was introduced – the Barcelona youngster was a surprise omission from Neto's team selection.
Midway through the half Nazareth found a pocket of space and drove towards the box before firing the ball superbly past goalkeeper Mary Earps for the equaliser.
"I felt the result was really fair for us. In the second half when we changed the formation, we were better," said Portugal boss Neto.
"When Kika [Nazareth] and other girls came in, they helped. This is something we want from all our players, to improve the team."
With the crowd buoyant and momentum clearly shifting in Portugal's favour, England were hanging on for the final whistle and despite a late header from Leah Williamson, were perhaps relieved in the end to come away with a point.
The result leaves them behind Nations League champions Spain, who came from 2-0 down earlier on Friday to beat Belgium 3-2 in the other match in Group A3.