The Runner= speed force well written IMO, The runner is fast as hell runs at warp speed and can increase by using his primodial powers if he wanted to. The Flash is fast but not fast enough against a being that was born to run since the dawn of time, only way flash can beat the runner he has to tap into the speedforce and that's not a guarantee that he can beat the runner because we haven't seen the runner true ability, like most beings he holds back.