what mlb team has the highest win percentage against another mlb team since 1900 including the playoffs

Since 1900, the Seattle Mariners have the highest winning percentage by a team against a team in the regular-season and playoffs, winning 77.8 percent of the time versus the Reds.

	TEAM	W%	OPP	W	L	G	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Mariners	.778	Reds	21	6	27	885	129	219	42	4	46	126	105	18	207	18	9	1,025	407	92	8	9	8	14	.247	.336	.460	.796
2	Yankees	.750	Cubs	27	9	36	1,269	198	339	58	3	50	191	154	13	263	21	7	1,458	553	111	13	9	7	23	.267	.350	.436	.786
3	Braves	.719	Athletics	23	9	32	1,080	156	265	58	6	45	151	89	11	212	23	6	1,195	470	109	7	8	4	19	.245	.307	.435	.742
4	Diamondbacks	.704	White Sox	19	8	27	903	151	231	45	8	36	145	79	8	188	18	4	1,009	400	89	4	15	3	19	.256	.316	.443	.759
5	Marlins	.681	Orioles	32	15	47	1,642	244	459	80	10	48	235	127	19	327	40	8	1,818	703	138	15	15	7	24	.280	.336	.428	.764
6	Cubs	.680	Orioles	17	8	25	862	123	237	50	7	34	123	66	7	185	16	2	948	403	91	5	8	1	13	.275	.329	.468	.796
7	Red Sox	.679	Marlins	36	17	53	1,815	309	532	115	11	58	294	174	19	369	33	14	2,042	843	184	11	23	12	45	.293	.357	.464	.821
8	Yankees	.677	Padres	21	10	31	1,037	144	255	43	2	42	135	94	8	237	31	4	1,152	428	87	3	10	10	20	.246	.311	.413	.723
9	Giants	.677	Guardians	21	10	31	1,001	118	232	48	2	21	109	103	9	223	18	9	1,136	347	71	13	10	4	24	.232	.306	.347	.653
10	White Sox	.676	Orioles	25	12	39	1,339	245	394	51	13	5	193	136	16	12	97		1,546	486	69	55				.294	.366	.363	.729
11	Reds	.667	Rays	18	9	27	903	131	218	39	4	34	121	96	18	247	21	6	1,027	367	77	7	3	4	12	.241	.325	.406	.732
12	Athletics	.667	Pirates	18	9	27	931	140	244	54	5	27	135	101	10	182	14	3	1,056	389	86	2	12	9	17	.262	.337	.418	.755
13	Dodgers	.667	Mariners	32	16	48	1,626	240	408	72	6	63	228	165	22	370	35	16	1,836	681	141	12	11	9	32	.251	.326	.419	.745
14	Red Sox	.667	Reds	22	11	33	1,126	169	296	73	6	36	165	118	6	257	12	7	1,268	489	115	8	10	11	23	.263	.333	.434	.768
15	Rebels	.659	Terrapins	29	15	46	1,516	191	410	65	27	7	159	115	16	173	56		1,713	550	99	66				.270	.328	.363	.691
16	Peppers	.659	Tip-Tops	29	15	44	1,480	233	421	66	22	5	182	154	9		64		1,704	546	93	61				.284	.355	.369	.724
17	Americans	.658	Orioles	25	13	38	1,394	239	426	53	39	9	205	76	8	-32	48		1,506	584	101	28				.306	.345	.419	.764
18	Braves	.657	Twins	23	12	35	1,250	176	344	61	6	57	170	104	9	253	18	4	1,376	588	124	7	6	7	27	.275	.334	.470	.804
19	Dodgers	.657	Twins	23	12	35	1,215	177	341	61	6	52	170	113	9	263	35	10	1,360	570	119	12	11	8	18	.281	.343	.469	.813
20	Twins	.656	Padres	21	11	32	1,086	147	275	48	1	40	143	91	19	232	27	8	1,216	445	89	14	6	8	19	.253	.320	.410	.730
21	Mariners	.654	Pirates	17	9	26	864	107	205	46	0	30	99	71	12	223	14	4	959	341	76	3	9	4	22	.237	.301	.395	.696
22	Nationals	.647	Mariners	22	12	34	1,121	141	284	50	3	41	140	98	8	229	23	11	1,250	463	94	13	10	7	32	.253	.315	.413	.728
23	Angels	.647	Rockies	33	18	51	1,783	304	518	95	8	82	290	177	22	348	37	12	2,008	875	185	9	17	11	48	.291	.359	.491	.849
24	Rays	.645	Diamondbacks	20	11	31	1,079	155	281	73	10	27	145	126	18	255	31	9	1,232	455	110	2	7	6	23	.260	.346	.422	.767
25	White Sox	.645	Giants	20	11	31	1,055	146	285	43	9	27	136	78	7	202	20	2	1,153	427	79	7	6	1	17	.270	.323	.405	.728