The first chance fell to Rayo's Alvaro Garcia, who shot wide inside the first minute. Madrid got on top after that, Vinicius Junior having a goal ruled out for offside and Benzema shooting over the bar before Kroos put them ahead after an intricate move involving Marco Asensio and Vinicius. Rayo goalkeeper Stole Dimitrievski reacted smartly to prevent an Alejandro Catena own goal and then Benzema made it 2-0 from David Alaba's pinpoint cross.
After half-time, Vinicius went close to scoring with a long, mazey dribble, Benzema curled over after Ferland Mendy's quick-thinking backheel and Asensio shot wide following tenacious work from Dani Carvajal. Bebe hit the post and substitute Radamel Falcao scored with a header to leave Madrid hanging onto the three points, clearing off the line in the final moments.
Real Madrid's defending has been hit and miss all year, but there's no doubt that in Alaba and Eder Militao they have two top ball-playing centre-backs, who will contribute plenty going forward. Alaba's left foot has caught the eye already -- just think of his Clasico goal against Barcelona -- but his cross for Benzema's goal here was as sweet a delivery as you'll see all season. One first-half Militao run, meanwhile, was reminiscent of Sergio Ramos at his rampaging best.
Asensio has been a frustrating player to watch for years now, and this season has been no exception. He's hugely talented, but at 25 has still not found a way to apply that talent with any consistency. He had played well once this year -- scoring a hat trick against Real Mallorca in a new midfield role -- before disappearing from view. Here, he played well back on the right wing, causing constant problems for Madrid youth product Fran Garcia.
Rayo have surprised everyone this season, looking remarkably well-organised and well-drilled -- and enjoyably adventurous -- for a newly promoted side under up-and-coming coach Andoni Iraola. They came to the Bernabeu ready, and caused Madrid problems as a result, especially towards the end at 2-1 when the home crowd got justifiably nervous.
Falcao hadn't played at the Bernabeu in eight years, since the 2013 Copa del Rey final, and had never scored at this stadium. The 35-year-old came off the bench with 20 minutes left and wasted no time in heading past Thibaut Courtois to set up a tense finale with Courtois saving the team in added time.
Manager rating out of 10
6 -- Carlo Ancelotti made just two changes to the team that beat Shakhtar Donetsk 2-1 in midweek, Eduardo Camavinga and Asensio coming in for Luka Modric and Lucas Vazquez. He is set on a familiar 4-3-3 for now, without too many tactical surprises. The team delivered here, taking two of their first-half chances, but came under serious pressure later when Ancelotti didn't seem to have the answers.
Player ratings (1-10; 10 = best, players introduced after 70 minutes get no rating)
GK Thibaut Courtois, 7 -- Had one or two saves to make, with a big one coming right at the end.
DF Dani Carvajal, 8 -- Celebrated his Spain call-up with his best performance this season. Found Benzema for Vinicius' offside goal and twice played Asensio into good positions.
DF David Alaba, 8 -- A glorious ball from the left for Benzema's goal, making taking out the entire Rayo defence look very, very easy. His third assist already.
DF Eder Militao, 7 -- Had the crowd cheering as he burst into the Rayo half with the ball in the opening 45 minutes.
DF Ferland Mendy, 7 -- Another solid display as he continues to forge a partnership with Vinicius on the left. A clever backheel set up Benzema to shoot over.
MF Toni Kroos, 8 -- Scored his first goal since April, opening the scoring when he finished a gorgeous team move really well.
MF Eduardo Camavinga, 6 -- Better than in his last start, when he came off at half-time against Osasuna, but not quite as effervescent as he was at the start of the season.
FW Marco Asensio, 7 -- His fourth start of the season, and his best performance since the Mallorca game. A persistent threat, which is exactly what he needs to be more often.
FW Vinicius Junior, 8 -- Thrilling every time he gets the ball now, and the crowd love him for it. Almost scored a goal-of-the-season contender.
FW Karim Benzema, 8 -- Now 14 goals in all competitions this season. The goal he scored was straightforward and looking back he'll think he should have grabbed a hat trick.
FW Eden Hazard, NR -- Won't get into the team ahead of Vinicius on the left. Tested here as a false nine, brought on for Benzema, without making an impact.
FW Lucas Vazquez, NR -- Replaced Asensio on the right.
DF Nacho, NR -- Thrown on to protect the lead in added time.