diff --git a/peer/peer.go b/peer/peer.go
index a174c5e9..4a57bc5f 100644
--- a/peer/peer.go
+++ b/peer/peer.go
@@ -947,11 +947,13 @@ func (p *Peer) handlePongMsg(msg *wire.MsgPong) {
 	// and overlapping pings will be ignored. It is unlikely to occur
 	// without large usage of the ping rpc call since we ping infrequently
 	// enough that if they overlap we would have timed out the peer.
+	p.statsMtx.Lock()
 	if p.lastPingNonce != 0 && msg.Nonce == p.lastPingNonce {
 		p.lastPingMicros = time.Since(p.lastPingTime).Nanoseconds()
 		p.lastPingMicros /= 1000 // convert to usec.
 		p.lastPingNonce = 0
 	}
+	p.statsMtx.Unlock()
 }
 
 // readMessage reads the next wire message from the peer with logging.