MANHATTAN, NY—It was an evening of guitar slinging at the first of a two-night stand at Madison Square Garden for Eric Clapton’s fourth installment of his Crossroads Guitar Festival to benefit the drug rehab center he founded in Antigua. Clapton put his Crossroads Centre drug rehabilitation clinic on the map in the mid-‘90s as a way of helping out others sort through their addictions and per his 2007 autobiography, “In order to stay sober, I had to help others get sober.”

Guitars twanged, banged and bolted into the blues for the five-hour marathon as the genre got twisted and shred but stayed true to its roots, as Clapton stood tall captaining the ship and steering the generational divide that went from the Chicago blues of BB King and Buddy Guy and back to 14-year-old Quinn Sullivan, who took his mentors’ licks and tossed them back in reverence to the masters.

John Mayer, Keith Urban, Doyle Bramhall II and Citizen Cope added a rocked out, countrified edge of urban twang to the mold as the show worked its way to the grand finale Allman Brothers set that Clapton poked a few riffs through. Robert Cray added his clean-cut, slinky ‘80s…