Sharks Can't Beat Strong Giant Orcas; They Can With Dolphins.
Tiger whales are not whales but belong to the dolphin family, the largest dolphin species, with high intelligence, adept at group warfare and strategic thinking. Tiger whales, as large 'dolphins', frighten sharks.
Dolphins we usually refer to also belong to the dolphin family, but their size differs greatly from tiger whales, but they are equally intelligent, adept at group warfare and strategic thinking.
When sharks encounter tiger whales, they cannot withstand them, but larger sharks can't necessarily contend with dolphins. Marine life still follows the basic 'big fish eat small fish' rule.

Even highly intelligent dolphins cannot take lightly of great white sharks, if they act alone, they will still become food for great whites. They are intelligent and adept at team strategies, but they don't suit the tiger whale's tactic of stunning sharks, because the success rate is too low and the risk is very high. In general, they don't like to fight great white sharks to the death, and risk avoidance is the priority.
Shark predation on high-intelligence dolphins is a reality in the ocean.
Besides tiger whales and several large black whales (two corys and false tiger whales), medium-sized predatory sharks are the main enemies of dolphins. Large great white sharks and tiger sharks (bull sharks) are also a considerable threat to false tiger whales and smaller corys.
A long-beaked dolphin corpse, washed ashore after being killed by a large shark (likely the great white shark). The various signs on the wound point to the killer being a shark – this is not an isolated case.

A half-width bowhead dolphin corpse in North Carolina.

A juvenile bowhead dolphin in New Jersey was bitten in half by a shark, and the shark's bite force cannot be underestimated.
Dolphins' reactions when facing sharks vary greatly, some flee in fear, and some effectively resist and drive away sharks through teamwork. In some groups, male dolphins will organize a defense line to protect female dolphins and young.

A bull shark (tiger shark) in Newcastle, New South Wales, Australia, seriously injured and killed a bowhead dolphin.
And dolphins have indeed been recorded to interfere or obstruct sharks to protect humans. Although not as magical and abundant as legends, most of the time the relationship between sharks and dolphins is that of hunter and prey. These dolphins' intelligence is not inferior to that of tiger whales, but they still need to run and evade when facing great whites.

A true dolphin (the blue shark was probably just passing by)... killed by a shark.

A fin-clipped dolphin bitten by a shortfin true shark (bull shark).
Dolphins are more likely to be attacked by sharks when searching for food near the coast.
Of course, dolphins can also kill sharks, and they have a 'shark killer' title, for example, they will attack nurse sharks, and even kill them. However, nurse sharks are very low in aggression and generally small in size, completely unlike fierce predatory sharks…

Dolphins attack nurse sharks… Poor little nurse shark, played with by dolphins, like a tiger whale plays with a great white shark! (Nurse shark: I'm not going to be a shark anymore!)