Rio Ferdinand claims Cristiano Ronaldo will already have urged his Manchester United teammates to make a key change to their attacking build-up.

Ronaldo, 36, marked his second debut for the Red Devils with two crucial goals in Saturday's 4-1 victory over Newcastle United on a historic day at Old Trafford.

The Portugal captain tapped in the opener from a rebound and powered his second through Freddie Woodman to restore the lead in the second half.

But Ferdinand insists Ronaldo was not entirely satisfied with his two-goal showing due to a lack of crosses, meaning he was unable to unleash his fearsome aerial ability.

"He can jump, but again it’s about positioning of where he’s going to be to receive the ball," Ferdinand told Vibe with FIVE YouTube channel of Ronaldo.

"That’s one thing that I would say, not a criticism, but one thing to look at and learn from, from Man United’s point of view from the weekend’s first game.

"And I’m telling you, he’d have been in there [the dressing room] after and this week saying, 'Listen, cross that ball! When you get opportunities to cross the ball, you put it in there because I’m aggressive and I want the ball'."

Former United centre-back Ferdinand believes Ronaldo is raring to "exploit" Premier League defenders who are no longer so comfortable in the air.

The Englishman added: "And he knows - and it’s well documented that I’ve always said this for the last few years - the defenders in this country are not great at defending crosses. It’s not an art that is actually honed anymore.

"When I was a kid, that was part and parcel of your daily routine, defending crosses, defending the box. From what I see in games, I don’t feel players are doing that enough.

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"Because when I see balls come in the box at the moment, body positions and angles etcetera are way off. And it isn’t easy as a defender, I can tell you I’ve made many mistakes in that position. But you’ve got to work at it.

"And I think he [Ronaldo] can exploit some naive defending at the moment in the Premier League."

When asked if United's full-backs should be swinging in more crosses for Ronaldo, Ferdinand responded: "That’s what I’m saying. That’s what he’ll be saying!

"When you get in those positions, or the wide players, you get out wide and there’s an opportunity to shift the ball and cross it, don’t turn out and think we’re going to keep the ball and recycle it and play possession football.

"If there’s an opportunity to cross it with someone like him in there, you cross it!"

Ferdinand added: "Play to the players’ and team’s strengths. And Cristiano, when the ball is wide, he attacks it better than anyone."