diff --git a/Libraries/LibWeb/CSS/Parser/Parser.cpp b/Libraries/LibWeb/CSS/Parser/Parser.cpp
index 069cbc06b6b..d948eae5344 100644
--- a/Libraries/LibWeb/CSS/Parser/Parser.cpp
+++ b/Libraries/LibWeb/CSS/Parser/Parser.cpp
@@ -192,14 +192,17 @@ RefPtr<Supports> Parser::parse_as_supports()
 template<typename T>
 RefPtr<Supports> Parser::parse_a_supports(TokenStream<T>& tokens)
 {
+    auto transaction = tokens.begin_transaction();
     auto component_values = parse_a_list_of_component_values(tokens);
     TokenStream<ComponentValue> token_stream { component_values };
     m_rule_context.append(RuleContext::SupportsCondition);
     auto maybe_condition = parse_boolean_expression(token_stream, MatchResult::False, [this](auto& tokens) { return parse_supports_feature(tokens); });
     m_rule_context.take_last();
     token_stream.discard_whitespace();
-    if (maybe_condition && !token_stream.has_next_token())
+    if (maybe_condition && !token_stream.has_next_token()) {
+        transaction.commit();
         return Supports::create(maybe_condition.release_nonnull());
+    }
 
     return {};
 }
diff --git a/Libraries/LibWeb/CSS/Parser/RuleParsing.cpp b/Libraries/LibWeb/CSS/Parser/RuleParsing.cpp
index 2c76197d269..a088669cb67 100644
--- a/Libraries/LibWeb/CSS/Parser/RuleParsing.cpp
+++ b/Libraries/LibWeb/CSS/Parser/RuleParsing.cpp
@@ -242,9 +242,8 @@ GC::Ptr<CSSImportRule> Parser::convert_to_import_rule(AtRule const& rule)
     if (tokens.next_token().is_function("supports"sv)) {
         auto component_value = tokens.consume_a_token();
         TokenStream supports_tokens { component_value.function().value };
-        if (supports_tokens.next_token().is_block()) {
-            supports = parse_a_supports(supports_tokens);
-        } else {
+        supports = parse_a_supports(supports_tokens);
+        if (!supports) {
             m_rule_context.append(RuleContext::SupportsCondition);
             auto declaration = consume_a_declaration(supports_tokens);
             m_rule_context.take_last();
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-cascade/parsing/supports-import-parsing.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-cascade/parsing/supports-import-parsing.txt
index b58337dfe22..046ae1cdb5f 100644
--- a/Tests/LibWeb/Text/expected/wpt-import/css/css-cascade/parsing/supports-import-parsing.txt
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-cascade/parsing/supports-import-parsing.txt
@@ -2,13 +2,13 @@ Harness status: OK
 
 Found 22 tests
 
-9 Pass
-13 Fail
+16 Pass
+6 Fail
 Pass	@import url("nonexist.css") supports(); should be an invalid import rule due to an invalid supports() declaration
 Pass	@import url("nonexist.css") supports(foo: bar); should be an invalid import rule due to an invalid supports() declaration
 Fail	@import url("nonexist.css") supports(display:block); should be a valid supports() import rule
 Fail	@import url("nonexist.css") supports((display:flex)); should be a valid supports() import rule
-Fail	@import url("nonexist.css") supports(not (display: flex)); should be a valid supports() import rule
+Pass	@import url("nonexist.css") supports(not (display: flex)); should be a valid supports() import rule
 Pass	@import url("nonexist.css") supports((display: flex) and (display: block)); should be a valid supports() import rule
 Pass	@import url("nonexist.css") supports((display: flex) or (display: block)); should be a valid supports() import rule
 Pass	@import url("nonexist.css") supports((display: flex) or (foo: bar)); should be a valid supports() import rule
@@ -17,12 +17,12 @@ Pass	@import url("nonexist.css") layer supports(); should be an invalid import r
 Pass	@import url("nonexist.css") layer supports(foo: bar); should be an invalid import rule due to an invalid supports() declaration
 Fail	@import url("nonexist.css") layer(A) supports((display: flex) or (foo: bar)); should be a valid supports() import rule
 Fail	@import url("nonexist.css") layer(A.B) supports((display: flex) and (foo: bar)); should be a valid supports() import rule
-Fail	@import url("nonexist.css") supports(selector(a)); should be a valid supports() import rule
-Fail	@import url("nonexist.css") supports(selector(p a)); should be a valid supports() import rule
-Fail	@import url("nonexist.css") supports(selector(p > a)); should be a valid supports() import rule
-Fail	@import url("nonexist.css") supports(selector(p + a)); should be a valid supports() import rule
-Fail	@import url("nonexist.css") supports(font-tech(color-colrv1)); should be a valid supports() import rule
-Fail	@import url("nonexist.css") supports(font-format(opentype)); should be a valid supports() import rule
+Pass	@import url("nonexist.css") supports(selector(a)); should be a valid supports() import rule
+Pass	@import url("nonexist.css") supports(selector(p a)); should be a valid supports() import rule
+Pass	@import url("nonexist.css") supports(selector(p > a)); should be a valid supports() import rule
+Pass	@import url("nonexist.css") supports(selector(p + a)); should be a valid supports() import rule
+Pass	@import url("nonexist.css") supports(font-tech(color-colrv1)); should be a valid supports() import rule
+Pass	@import url("nonexist.css") supports(font-format(opentype)); should be a valid supports() import rule
 Fail	@import url(nonexist.css) supports(display:block); should be a valid supports() import rule
 Fail	@import "nonexist.css" supports(display:block); should be a valid supports() import rule
 Pass	@import url("nonexist.css") supports; should still be a valid import rule with an invalid supports() declaration
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