David Barron's three-year-old needed lots of persuasion from jockey Ben Curtis, but he eventually got the job done with a degree of authority.
Oisin Murphy was keen to get into a commanding position aboard 10-11 favourite Dawn Dancer and was in the lead for a long way.
But Kripke's stamina came into play inside the final two furlongs and he ended up winning by six lengths from the market leader.
Curtis said of the 15-8 chance: "He's just a big, raw horse.
"He stays well and that played to his strengths.
"I thought if I could keep on his (Dawn Dancer's) coat-tails I knew he'd stay the trip well."
Murphy had better fortune earlier in the day when Warrior's Valley (7-2) made no mistake in the Betway Sprint Handicap.
David Griffiths' three-year-old was getting weight from the full field and ably cashed in with a two-and-a-quarter-length defeat of Silver Penny.
Griffiths told At The Races: "I've always thought quite a bit of him, but it's taken a bit of time for the penny to drop.
"Hopefully we can go on from that now."
Select any odd to add a bet