Pacing was combat technique, known to multiple species, in which one starship precisely matches the speed of a second vessel while maintaining a parallel heading, all while shadowing, or remaining outside phaser range at the extreme limit of sensor range.
The Orions employed this tactic while the USS Enterprise was en route to Babel in 2268. The Orion scout ship had been pacing the Enterprise for five minutes, until the latter ship moved to intercept. In response, the scout ship changed course towards the Enterprise, passing it at close range while traveling at warp factor 10. (TOS: "Journey to Babel")
Later that year, the Klingons paced the Enterprise while the ship was en route to Troyius. Initially the Klingon warship appeared as a sensor ghost until it moved into contact range, forcing the Enterprise to maintain yellow alert. (TOS: "Elaan of Troyius")