This study used small-sided games (SSGs) to induce fatigue and therefore, reduce the action capabilities of British Varsity soccer players (n = 20). The aim was to examine the effect of compromised action capabilities on the defensive movement response of players in a 1 vs 1 scenario. Action capabilities were assessed via countermovement jumps (CMJ), 5-m acceleration, 20-m sprint and a pre-planned Change of Direction (COD) Test. Defensive movement response was measured via a Soccer-Specific Anticipation Test (SSAT), which required players to anticipate the change of direction of an attacking player. Following the SSGs fatigue intervention, significant reductions were observed in jump (p = .04, d = .31), acceleration (p <.001, d = .98), and sprint (p < .001, d = .66) performance. Significantly, players tended to move earlier in the SSAT following the SSGs fatigue intervention than they had before the SSGs (p = .049, d = .66). Furthermore, to examine the distinct effect of reductions in each action capability, players were categorised according to whether the SSGs fatigue intervention had a worthwhile change in CMJ, acceleration, sprint or pre-planned COD. For each of the four measures, defensive movements tended to be initiated earlier following the SSGs fatigue intervention; although pre-/post-SSGs differences were not significant (p = .08-.51), moderate to large effect sizes were shown (d = .56-.84). The findings of this study intimate that reductions in action capabilities influence the timing of the movement response of defensive players in 1-vs-1 situations.