diff --git a/lib/controller/controller.py b/lib/controller/controller.py
index 84d0adf59..48dcef055 100644
--- a/lib/controller/controller.py
+++ b/lib/controller/controller.py
@@ -217,6 +217,8 @@ def start():
                         testSqlInj = True
                         paramKey = (conf.hostname, conf.path, place, parameter)
 
+                        conf.matchRatio = None
+
                         if paramKey in kb.testedParams:
                             testSqlInj = False
 
@@ -242,14 +244,14 @@ def start():
                         if testSqlInj:
                             heuristicCheckSqlInjection(place, parameter, value)
 
+                            conf.matchRatio = None
+
                             for parenthesis in range(0, 4):
                                 logMsg  = "testing sql injection on %s " % place
                                 logMsg += "parameter '%s' with " % parameter
                                 logMsg += "%d parenthesis" % parenthesis
                                 logger.info(logMsg)
 
-                                conf.matchRatio = None
-
                                 injType = checkSqlInjection(place, parameter, value, parenthesis)
 
                                 if injType:
diff --git a/lib/request/comparison.py b/lib/request/comparison.py
index 5c3009c94..f68ae891b 100644
--- a/lib/request/comparison.py
+++ b/lib/request/comparison.py
@@ -20,6 +20,10 @@ def comparison(page, headers=None, getSeqMatcher=False, pageLength=None):
     if page is None and pageLength is None:
         return None
 
+    # In case of an DBMS error page return None
+    if wasLastRequestError():
+        return None
+
     regExpResults = None
 
     if page:
@@ -105,10 +109,6 @@ def comparison(page, headers=None, getSeqMatcher=False, pageLength=None):
     if getSeqMatcher:
         return ratio
 
-    # In case of an DBMS error page return None
-    elif wasLastRequestError():
-        return None
-
     elif ratio == 1:
         return True