diff --git a/src/plugin/customParseFormat/index.js b/src/plugin/customParseFormat/index.js
index ee7bd5cfb..cffbffbbb 100644
--- a/src/plugin/customParseFormat/index.js
+++ b/src/plugin/customParseFormat/index.js
@@ -47,13 +47,13 @@ const expressions = {
     this.milliseconds = +input
   }],
   s: [match1to2, addInput('seconds')],
-  ss: [match2, addInput('seconds')],
+  ss: [match1to2, addInput('seconds')],
   m: [match1to2, addInput('minutes')],
-  mm: [match2, addInput('minutes')],
+  mm: [match1to2, addInput('minutes')],
   H: [match1to2, addInput('hours')],
   h: [match1to2, addInput('hours')],
-  HH: [match2, addInput('hours')],
-  hh: [match2, addInput('hours')],
+  HH: [match1to2, addInput('hours')],
+  hh: [match1to2, addInput('hours')],
   D: [match1to2, addInput('day')],
   DD: [match2, addInput('day')],
   M: [match1to2, addInput('month')],
diff --git a/test/plugin/customParseFormat.test.js b/test/plugin/customParseFormat.test.js
index 1b2bef219..eb2f2204b 100644
--- a/test/plugin/customParseFormat.test.js
+++ b/test/plugin/customParseFormat.test.js
@@ -73,12 +73,30 @@ it('timezone with no hour', () => {
   expect(dayjs(input, format).valueOf()).toBe(moment(input, format).valueOf())
 })
 
-it('parse just hh:mm)', () => {
+it('parse hh:mm', () => {
   const input = '12:00'
   const format = 'hh:mm'
   expect(dayjs(input, format).valueOf()).toBe(moment(input, format).valueOf())
 })
 
+it('parse HH:mm:ss', () => {
+  const input = '00:27:21'
+  const format = 'HH:mm:ss'
+  expect(dayjs(input, format).valueOf()).toBe(moment(input, format).valueOf())
+})
+
+it('parse HH:mm:ss but only one digit', () => {
+  const input = '0:0:1'
+  const format = 'HH:mm:ss'
+  expect(dayjs(input, format).valueOf()).toBe(moment(input, format).valueOf())
+})
+
+it('parse hh:mm:ss but only one digit', () => {
+  const input = '0:0:1'
+  const format = 'hh:mm:ss'
+  expect(dayjs(input, format).valueOf()).toBe(moment(input, format).valueOf())
+})
+
 it('fails with an invalid format', () => {
   const input = '2018-05-02 12:00 PM'
   const format = 'C'