Real, now 13-time European Cup winners, are the first team to win the competition in three successive seasons since Bayern Munich between 1974 and 1976.
Karius was embarrassed minutes later, however, as he tried to quickly release Dejan Lovren with Benzema in close proximity and the Real striker's decision to stick out a boot paid off handsomely with the 51st minute opener.
The English side attacked with intent and Trent Alexander-Arnold tested Navas with a low drive but Real looked in charge following the departure, in tears, of Salah.
In the tunnel before kickoff there was a furtive glance across to Salah, but the showdown between the world player of the year and a contender for his throne never materialized. Having settled on Karius ahead of Simon Mignolet over recent months, Klopp's faith backfired and he is the fourth manager after Massimiliano Allegri, Diego Simeone and Hector Cuper to lose in two Champions League finals.
It's not clear if the diminutive forward will be able to play in the World Cup, which starts in three weeks.
Real Madrid play Liverpool at Kiev's Olympic Stadium in the final of the 2017/18 edition of the UEFA Champions League.
Not for long. Salah's final was over after 30 minutes.
Four minutes later, the tears were flowing down the face of Carvajal after the Madrid right back appeared to injure a hamstring while attempting a back-heel. They also look more secure aerially, which was a big concern earlier in the season. From long-distance Bale sent in a dipping ball and Karius made a mess of it, allowing the ball to roll off his fists and into net to make it 3-1 to Real.
For Madrid it was about one man proving Zidane wrong. "We're in a third final and we have the chance to do something historic", he said.
"I felt like I deserved it but the manager makes the decisions and what can you do?"
Bale scored twice during the 3-1 win over Liverpool in Kiev, slamming home an outrageous overhead kick and beating Loris Karius with a long-range strike.