diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c
index efc5284e5b1..9f8277bf8fa 100644
--- a/src/backend/access/nbtree/nbtsearch.c
+++ b/src/backend/access/nbtree/nbtsearch.c
@@ -1026,6 +1026,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
 				 */
 				if (chosen == NULL)
 					break;
+				chosen->sk_flags |= SK_BT_BT_FIRST;
 				startKeys[keysCount++] = chosen;
 
 				/*
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c
index 1510b97fbe1..84c4022201a 100644
--- a/src/backend/access/nbtree/nbtutils.c
+++ b/src/backend/access/nbtree/nbtutils.c
@@ -1400,7 +1400,7 @@ _bt_checkkeys(IndexScanDesc scan, IndexTuple tuple, int tupnatts,
 		bool		isNull;
 		Datum		test;
 		bool		requiredSameDir = false,
-					requiredOppositeDir = false;
+					guaranteedByBtFirst = false;
 
 		/*
 		 * Check if the key is required for ordered scan in the same or
@@ -1409,9 +1409,10 @@ _bt_checkkeys(IndexScanDesc scan, IndexTuple tuple, int tupnatts,
 		if (((key->sk_flags & SK_BT_REQFWD) && ScanDirectionIsForward(dir)) ||
 			((key->sk_flags & SK_BT_REQBKWD) && ScanDirectionIsBackward(dir)))
 			requiredSameDir = true;
-		else if (((key->sk_flags & SK_BT_REQFWD) && ScanDirectionIsBackward(dir)) ||
-				 ((key->sk_flags & SK_BT_REQBKWD) && ScanDirectionIsForward(dir)))
-			requiredOppositeDir = true;
+		else if ((((key->sk_flags & SK_BT_REQFWD) && ScanDirectionIsBackward(dir)) ||
+				 ((key->sk_flags & SK_BT_REQBKWD) && ScanDirectionIsForward(dir))) &&
+				 (key->sk_flags & SK_BT_BT_FIRST))
+			guaranteedByBtFirst = true;
 
 		/*
 		 * Is the key required for scanning for either forward or backward
@@ -1419,7 +1420,7 @@ _bt_checkkeys(IndexScanDesc scan, IndexTuple tuple, int tupnatts,
 		 * known to be matched, skip the check.  Except for the row keys,
 		 * where NULLs could be found in the middle of matching values.
 		 */
-		if ((requiredSameDir || requiredOppositeDir) &&
+		if ((requiredSameDir || guaranteedByBtFirst) &&
 			!(key->sk_flags & SK_ROW_HEADER) && requiredMatchedByPrecheck)
 			continue;
 
@@ -1526,7 +1527,7 @@ _bt_checkkeys(IndexScanDesc scan, IndexTuple tuple, int tupnatts,
 		 * _bt_first() except for the NULLs checking, which have already done
 		 * above.
 		 */
-		if (!requiredOppositeDir)
+		if (!guaranteedByBtFirst)
 		{
 			test = FunctionCall2Coll(&key->sk_func, key->sk_collation,
 									 datum, key->sk_argument);
diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h
index 7bfbf3086c8..e7783621a2b 100644
--- a/src/include/access/nbtree.h
+++ b/src/include/access/nbtree.h
@@ -1090,6 +1090,7 @@ typedef BTScanOpaqueData *BTScanOpaque;
  */
 #define SK_BT_REQFWD	0x00010000	/* required to continue forward scan */
 #define SK_BT_REQBKWD	0x00020000	/* required to continue backward scan */
+#define SK_BT_BT_FIRST	0x00040000	/* used for _bt_first() */
 #define SK_BT_INDOPTION_SHIFT  24	/* must clear the above bits */
 #define SK_BT_DESC			(INDOPTION_DESC << SK_BT_INDOPTION_SHIFT)
 #define SK_BT_NULLS_FIRST	(INDOPTION_NULLS_FIRST << SK_BT_INDOPTION_SHIFT)