Sydney McLaughlin took the last victorious lap of an all-American world championships. She pulled away in the 4-by-400 relay to close a U.S. runaway and give the Americans their record 33rd medal for the meet. McLaughlin turned a .73-second lead into a 2.93-second runaway on the anchor lap, adding this burst of speed to the world record she set two nights earlier in the 400 hurdles. Two more world records went down — in the very first and very last action of the last session at Hayward Field. Nigeria’s Tobi Amusan opened the evening by setting the record for the 100-meter hurdles in the semifinals: 12.12 seconds. And, pole vaulter Armand Duplantis of Sweden cleared 6.21 meters (20 feet, 4 1/2 inches) to best his world record.