We find evidence for an infrared fixed point in perturbative QCD using two complementary approximations: The Banks-Zaks expansion and the large-b resummations. Analyzing the e\sp+e\sp− annihilation ratio and the polarized Bjorken-sum-rule of deep-inelastic-scattering, we use the recent calculation of the renormalization-group β-function to four-loops in QCD to confirm that the Banks-Zaks expansion is relevant when extrapolated from sixteen down to two light quark flavors. We also search for indications of infrared 'freezing' in the Borel-renormalon-inspired 'large-b' resummations. We find the 'large-b' approximation also indicates perturbative 'freezing' of the e\sp+e\sp− annihilation ratio and the polarized Bjorken-sum-rule at leading order. Finally, we study the region, n\sbf = 2, where the 'large-n\sbf' resummation and Banks-Zaks expansion complement one another. We conclude that there is strong evidence for the existence of a perturbative infrared fixed point in the Standard Model QCD.