We prove exponential correlation decay in dispersing billiard flows on the 2-torus assuming finite horizon and lack of corner points. With applications aimed at describing heat conduction, the highly singular initial measures are concentrated here on 1-dimensional submanifolds (given by standard pairs) and the observables are supposed to satisfy a generalized Hölder continuity property. The result is based on the exponential correlation decay bound of Baladi, Demers and Liverani [1] obtained for Hölder continuous observables in these billiards. The model dependence of the bounds is also discussed.describe the regularity of the billiard table Q for our purposes. In most of our calculations, constants that depend only on the billiard table Q, will actually depend on Q only through these regularity parameters. Note that the bounds τ min , τ max , κ min , κ max , κ ′ max , K max , d Q need not be sharp, so the estimates we give are uniform for the class of billiard tables satisfying the same bounds. Theorem 2.7 (Uniform hyperbolicity). There are constants λProof. In this whole section we assume that F : M → R is generalized α F -Hölder continuous (cf. Definition 2.12) and that M F dµ = 0. The analogous property for the billiard map is stated in Corollary 4.20 and Formula (4.19) in [12]. As formulated in Theorem 2.7, the statement follows from the definition of α min and the expansion properties of dispersing wave fronts, in particular Formulas (3.35) and (4.9) in [12]. See also Lemma 3.3 in [1].Theorem 2.8 (Transversality). There is a constant c tr = c tr (R Q , R u ) > 0 such that any u-curve and any central-stable manifold intersecting it have an angle at least c tr at their intersection point.