• U.S. relay team disqualified, then reinstated.

The U.S. men have a long history of dicey baton exchanges in the Olympic relays. So do the U.S. women.

Their latest was a firstof-its-kind chance to flub one together, which they might have, but they caught a break that gives them a chance to still win a medal.

In the Olympic debut of the 4x400-meter mixed relay, the U.S. was disqualified for a bad exchange, only to be reinstated after filing a t protest.

Officials originally ruled that Lynna Irby had positioned herself outside the passing zone when she received the exchange from Elija Godwin in Friday night’s preliminary heat.

Later, they overturned that decision on appeal. USA Track and Field announced the change but did not provide details of what happened. The Dominican Republic also had been disqualified but was later reinstated.

In the 4x400, officials direct the next group of runners onto the track to try to maintain a semblance of order in the sometimescrowded exchange zone. Runners can be every bit as attuned to where the officials tell them to line up as to the teammate about to give them the baton.

• Nigerian sprinter Blessing Okagbare was disqualified from competing in the Olympic Games Saturday after testing positive for human growth hormone

in the first failed drug test of these Games.

The announcement by the Athletics Integrity Unit, which handles anti-doping for track’s worldwide governing body, came just hours after she won her Olympic 100 meter heat Friday night and with Okagbare scheduled to compete in the 200 semifinals Saturday night.

The positive results for Okagbare, an Olympic silver medalist in the long jump, were from a no advance notice, out-of-competition test conducted on July 19, AIU said.

Ten Nigerians were among 18 athletes banned from competing in Tokyo by the AIU for not meeting out-of-competition testing requirements.