3 things we learned from Real Madrid's victory over wasteful Roma

Roma had every chance to overturn a 2-0 deficit in the second leg of its last-16 Champions League tie against Real Madrid, but on three inviting occasions, the Giallorossi failed to capitalize.

By the 64th minute, Cristiano Ronaldo had scored for Madrid, and when James Rodriguez slipped in a second goal moments later, a night full of opportunity for Roma had officially ended.

Related - VIDEO: Ronaldo's 90th Champions League goal all but eliminates Roma

Having avoided an upset, Madrid will look forward to a sixth straight quarter-final appearance in the Champions League. Roma, meanwhile, will travel back home thinking of what could've been.

Dzeko too hesitant to lead Roma's line

All alone at the tip of the box, Edin Dzeko had Roma's first sight of the Madrid goal in the 14th minute, but he could only muster a shot wide of the net.

It was the tale of the Bosnian's season: He simply doesn't have the confidence a top No. 9 needs, especially in a tough setting like the Bernabeu. And it's not as if Dzeko hasn't shouldered this kind of pressure before: he played and scored in Manchester City's wild 3-2 loss to Madrid in 2012 in the same stadium.

His sudden lack of poise should bother Roma supporters, who thought they were solving a long-unanswered riddle in the striker position when Dzeko signed from City this summer. He doesn't have the determination to take on defenders or test the 'keeper from different positions.

Manager Luciano Spalletti believes in Dzeko's abilities, saying before the match he is putting in the necessary work, but at some point Dzeko actually has to show what he's capable of doing. The mentality has to change.

Navas truly a big-game goalkeeper

Keylor Navas is putting together quite a resume. He has kept clean sheets in all eight of his Champions League appearances, going a total of 720 minutes without conceding a goal. He is now roughly a game-and-a-half away from breaking the all-time record set by ex-Arsenal netminder Jens Lehmann at 853 minutes.

He made four saves on Tuesday against Roma, using his feet to deny Kostas Manolas in the second half and diving to palm away a late strike from Diego Perotti, his best stop of the night.

Navas' performances in the 2014 World Cup for Costa Rica initially earned him worldwide recognition, but he's since proved that he thrives in the spotlight:

Ronaldo keeps meeting high standards

Ronaldo finished the night with 14 of Madrid's 37 shots against Roma, looking rather profligate, but he eventually scored the goal that killed the tie, and assisted the second in the 2-0 win. It was his 90th in the tournament - and his 40th across all competitions this season. He continues to levitate above the rest of the pack:

Critics have come out this season to chastise Ronaldo for his apparent shortcomings against stronger opponents, but he has now scored in every Round of 16 match for five years straight. His consistency at the top level is remarkable. Of those 90 goals he's scored in Europe's premier competition, 44 have come at home, another 44 have come on the road, and the other two on neutral soil.

"Every time Cristiano is on the pitch he wants to score," said manager Zinedine Zidane, "and he keeps doing it."