diff --git a/app/vmselect/promql/rollup.go b/app/vmselect/promql/rollup.go
index 3bb5f8463..cedcf1958 100644
--- a/app/vmselect/promql/rollup.go
+++ b/app/vmselect/promql/rollup.go
@@ -1308,8 +1308,11 @@ func rollupDelta(rfa *rollupFuncArg) float64 {
 			// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/894
 			return values[len(values)-1] - rfa.realPrevValue
 		}
-		// Assume that the previous non-existing value was 0
-		// only if the first value doesn't exceed too much the delta with the next value.
+		// Assume that the previous non-existing value was 0 only in the following cases:
+		//
+		// - If the delta with the next value equals to 0.
+		//   This is the case for slow-changing counter - see https://github.com/VictoriaMetrics/VictoriaMetrics/issues/962
+		// - If the first value doesn't exceed too much the delta with the next value.
 		//
 		// This should prevent from improper increase() results for os-level counters
 		// such as cpu time or bytes sent over the network interface.
@@ -1317,12 +1320,15 @@ func rollupDelta(rfa *rollupFuncArg) float64 {
 		//
 		// This also should prevent from improper increase() results when a part of label values are changed
 		// without counter reset.
-		d := float64(10)
+		var d float64
 		if len(values) > 1 {
 			d = values[1] - values[0]
 		} else if !math.IsNaN(rfa.realNextValue) {
 			d = rfa.realNextValue - values[0]
 		}
+		if d == 0 {
+			d = 10
+		}
 		if math.Abs(values[0]) < 10*(math.Abs(d)+1) {
 			prevValue = 0
 		} else {
diff --git a/app/vmselect/promql/rollup_test.go b/app/vmselect/promql/rollup_test.go
index ad9a7b7e4..b736d6259 100644
--- a/app/vmselect/promql/rollup_test.go
+++ b/app/vmselect/promql/rollup_test.go
@@ -1171,8 +1171,16 @@ func TestRollupDelta(t *testing.T) {
 	f(nan, nan, nan, []float64{5, 6, 8}, 8)
 	f(2, nan, nan, []float64{5, 6, 8}, 6)
 
-	// Too big initial value must be skipped.
+	// Moderate initial value with zero delta after that.
+	// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/962
+	f(nan, nan, nan, []float64{100}, 100)
+	f(nan, nan, nan, []float64{100, 100}, 100)
+
+	// Big initial value with with zero delta after that.
 	f(nan, nan, nan, []float64{1000}, 0)
+	f(nan, nan, nan, []float64{1000, 1000}, 0)
+
+	// Big initial value with small delta after that.
 	f(nan, nan, nan, []float64{1000, 1001, 1002}, 2)
 
 	// Non-nan realPrevValue
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 47cdf0c41..0b50310fe 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -21,6 +21,7 @@
 * BUGFIX: do not enable strict parsing for `-promscrape.config` if `-promscrape.config.dryRun` comand-line flag is set. Strict parsing can be enabled with `-promscrape.config.strictParse` command-line flag. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/944
 * BUGFIX: vminsert: properly update `vm_rpc_rerouted_rows_processed_total` metric. Previously it wasn't updated. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/955
 * BUGFIX: vmagent: properly recover when opening incorrectly stored persistent queue. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/964
+* BUGFIX: assume the previous value is 0 when calculating `increase()` for the first point on the graph if its value doesn't exceed 100 and the delta between two first points equals to 0. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/962
 
 
 # [v1.49.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.49.0)