With light rods and light tippets, big fish can be landed on a very light rod if you play the fish off the reel and don't try to land it by stripping line in and clamping the line to the grip. You need a reel with a good/light drag that is set below the breaking point of the tippet and the rod. When in doubt, set the drag very low and palm the reel to add drag. You should test the drag setting and determine how much bend the rod can handle. Tie the line to something solid, reel in the slack and pull back on the rod until you think the rod/tippet is at risk of breaking. Set the drag to slip before that point. And remember how much the rod was bent when it started to slip and never exceed that bend when you are fighting a fish.
To keep from exceeding the break point during a fight, do not allow the rod to bend into a horseshoe. Fight the fish with the rod at no more than a 45 degree angle, allowing the drag of the reel to give line on surges or power runs. Do not clamp down on the line with your hand to stop a run, palm the reel but avoid exceeding a safe bend. The fish will tire, be patient. In a river, get below the fish to make the fish fight the current as well as the rod.
Also, when you land a fish, don't high stick the rod (point it straight up when the fish is at your feet). If the fish dives, there is no rod flex to cushion the run and the tip can snap.
We sometimes fish with 2, 3, and 4 wt rods for schoolie striped bass and catch 20-25" fish. Bigger fish are possible if they are present. We also use 8-15# leaders, so a light rod will break before the leader snaps if you don't use a good drag and fighting techniques.