diff --git a/core/src/states/kickoff.rs b/core/src/states/kickoff.rs
index c701f472..d13d1607 100644
--- a/core/src/states/kickoff.rs
+++ b/core/src/states/kickoff.rs
@@ -20,7 +20,7 @@ use super::{
     Owner,
 };
 
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
 pub enum KickoffEvent {
     Challenged,
     WatchtowerChallengeSent {
@@ -72,12 +72,12 @@ impl<T: Owner> BlockMatcher for KickoffStateMachine<T> {
         self.matchers
             .iter()
             .filter_map(|(matcher, kickoff_event)| {
-                if matcher.matches(block) {
-                    Some(kickoff_event.clone())
-                } else {
-                    None
-                }
+                matcher.matches(block).map(|ord| (ord, kickoff_event))
             })
+            .min()
+            .map(|(_, kickoff_event)| kickoff_event)
+            .into_iter()
+            .cloned()
             .collect()
     }
 }
@@ -126,6 +126,12 @@ impl<T: Owner> KickoffStateMachine<T> {
     ) {
         tracing::debug!(?self.kickoff_id, "Dispatching event {:?}", evt);
         self.dirty = true;
+
+        // Remove the matcher corresponding to the event.
+        if let Some((matcher, _)) = self.matchers.iter().find(|(_, ev)| ev == &evt) {
+            let matcher = matcher.clone();
+            self.matchers.remove(&matcher);
+        }
     }
 
     async fn check_time_to_send_asserts(&mut self, context: &mut StateContext<T>) {
diff --git a/core/src/states/matcher.rs b/core/src/states/matcher.rs
index 3b01e845..c6b684dd 100644
--- a/core/src/states/matcher.rs
+++ b/core/src/states/matcher.rs
@@ -1,14 +1,16 @@
+use std::cmp::Ordering;
+
 use super::block_cache::BlockCache;
 use bitcoin::{OutPoint, Txid};
 
 pub(crate) trait BlockMatcher {
     type StateEvent;
 
-    fn match_block(&self, block: &super::block_cache::BlockCache) -> Vec<Self::StateEvent>;
+    fn match_block(& self, block: &super::block_cache::BlockCache) -> Vec<Self::StateEvent>;
 }
 
 // Matcher for state machines to define what they're interested in
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
 pub enum Matcher {
     SentTx(Txid),
     SpentUtxo(OutPoint),
@@ -18,16 +20,50 @@ pub enum Matcher {
     BlockHeight(u32),
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum MatcherOrd {
+    TxIndex(usize),
+    BlockHeight,
+}
+
+impl PartialOrd for MatcherOrd {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        match (self, other) {
+            (MatcherOrd::TxIndex(a), MatcherOrd::TxIndex(b)) => a.partial_cmp(b),
+            (MatcherOrd::BlockHeight, MatcherOrd::BlockHeight) => Some(Ordering::Equal),
+            (MatcherOrd::BlockHeight, _) => Some(Ordering::Less),
+            (_, MatcherOrd::BlockHeight) => Some(Ordering::Greater),
+        }
+    }
+}
+
+impl Ord for MatcherOrd {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.partial_cmp(other)
+            .expect("partial_cmp always returns Some")
+    }
+}
+
 impl Matcher {
-    // TODO: sort by matched tx index
-    pub fn matches(&self, block: &BlockCache) -> bool {
+    pub fn matches(&self, block: &BlockCache) -> Option<MatcherOrd> {
         match self {
-            Matcher::SentTx(txid) => block.contains_txid(txid),
-            Matcher::SpentUtxo(outpoint) => block.is_utxo_spent(outpoint),
-            Matcher::BlockHeight(height) => *height <= block.block_height,
-            Matcher::SpentUtxoButNotTimeout(outpoint, txid) => {
-                block.is_utxo_spent(outpoint) && !block.contains_txid(txid)
+            Matcher::SentTx(txid) if block.contains_txid(txid) => Some(MatcherOrd::TxIndex(
+                block.txids.get(txid).expect("txid is in cache").clone(),
+            )),
+            Matcher::SpentUtxo(outpoint) if (block.is_utxo_spent(outpoint)) => Some(
+                MatcherOrd::TxIndex(*block.spent_utxos.get(outpoint).expect("utxo is in cache")),
+            ),
+            Matcher::BlockHeight(height) if *height <= block.block_height => {
+                Some(MatcherOrd::BlockHeight)
+            }
+            Matcher::SpentUtxoButNotTimeout(outpoint, txid)
+                if block.is_utxo_spent(outpoint) && !block.contains_txid(txid) =>
+            {
+                Some(MatcherOrd::TxIndex(
+                    *block.spent_utxos.get(outpoint).expect("utxo is in cache"),
+                ))
             }
+            _ => None,
         }
     }
 }
diff --git a/core/src/states/round.rs b/core/src/states/round.rs
index 405c8456..4dbb79c5 100644
--- a/core/src/states/round.rs
+++ b/core/src/states/round.rs
@@ -1,6 +1,9 @@
 use eyre::Context;
 use statig::prelude::*;
-use std::collections::{HashMap, HashSet};
+use std::{
+    collections::{HashMap, HashSet},
+    ops::DerefMut,
+};
 
 use crate::{
     builder::{
@@ -17,7 +20,7 @@ use super::{
     Owner,
 };
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Eq, PartialEq, Hash, Ord, PartialOrd)]
 pub enum RoundEvent {
     KickoffUtxoUsed { kickoff_idx: usize },
     ReadyToReimburseSent { round_idx: u32 },
@@ -40,12 +43,12 @@ impl<T: Owner> BlockMatcher for RoundStateMachine<T> {
         self.matchers
             .iter()
             .filter_map(|(matcher, round_event)| {
-                if matcher.matches(block) {
-                    Some(round_event.clone())
-                } else {
-                    None
-                }
+                matcher.matches(block).map(|ord| (ord, round_event))
             })
+            .min()
+            .map(|(_, round_event)| round_event)
+            .into_iter()
+            .cloned()
             .collect()
     }
 }
@@ -100,6 +103,12 @@ impl<T: Owner> RoundStateMachine<T> {
     ) {
         tracing::debug!(?self.operator_data, ?self.operator_idx, "Dispatching event {:?}", evt);
         self.dirty = true;
+
+        // Remove the matcher corresponding to the event.
+        if let Some((matcher, _)) = self.matchers.iter().find(|(_, ev)| ev == &evt) {
+            let matcher = matcher.clone();
+            self.matchers.remove(&matcher);
+        }
     }
 
     #[state(entry_action = "on_initial_collateral_entry")]