diff --git a/clientv3/balancer.go b/clientv3/balancer.go
index b7767221ac7a..b9d543b49ea3 100644
--- a/clientv3/balancer.go
+++ b/clientv3/balancer.go
@@ -89,6 +89,7 @@ func newSimpleBalancer(eps []string) *simpleBalancer {
 		updateAddrsC: make(chan struct{}, 1),
 		host2ep:      getHost2ep(eps),
 	}
+	close(sb.downc)
 	go sb.updateNotifyLoop()
 	return sb
 }
@@ -170,38 +171,55 @@ func (b *simpleBalancer) updateNotifyLoop() {
 
 	for {
 		b.mu.RLock()
-		upc := b.upc
+		upc, downc := b.upc, b.downc
 		b.mu.RUnlock()
-		var downc chan struct{}
+		// downc or upc should be closed
+		select {
+		case <-downc:
+			downc = nil
+		default:
+		}
 		select {
 		case <-upc:
-			var addr string
-			b.mu.RLock()
-			addr = b.pinAddr
-			// Up() sets pinAddr and downc as a pair under b.mu
-			downc = b.downc
-			b.mu.RUnlock()
-			if addr == "" {
-				break
+			upc = nil
+		case <-b.stopc:
+			return
+		default:
+		}
+		switch {
+		case downc == nil && upc == nil:
+			// stale
+		case downc == nil:
+			b.notifyAddrs()
+			select {
+			case <-upc:
+				b.mu.RLock()
+				addr := b.pinAddr
+				b.mu.RUnlock()
+				if addr == "" {
+					break
+				}
+				// close opened connections that are not pinAddr
+				// this ensures only one connection is open per client
+				select {
+				case b.notifyCh <- []grpc.Address{{Addr: addr}}:
+				case <-b.stopc:
+					return
+				}
+			case <-b.updateAddrsC:
+				b.notifyAddrs()
+				continue
+			case <-b.stopc:
+				return
 			}
-			// close opened connections that are not pinAddr
-			// this ensures only one connection is open per client
+		case upc == nil:
 			select {
-			case b.notifyCh <- []grpc.Address{{Addr: addr}}:
+			case <-downc:
+			case <-b.updateAddrsC:
+				b.notifyAddrs()
 			case <-b.stopc:
 				return
 			}
-		case <-b.updateAddrsC:
-			b.notifyAddrs()
-			continue
-		}
-		select {
-		case <-downc:
-			b.notifyAddrs()
-		case <-b.updateAddrsC:
-			b.notifyAddrs()
-		case <-b.stopc:
-			return
 		}
 	}
 }
@@ -231,16 +249,15 @@ func (b *simpleBalancer) Up(addr grpc.Address) func(error) {
 	if !hasAddr(b.addrs, addr.Addr) {
 		return func(err error) {}
 	}
-
-	if b.pinAddr == "" {
-		// notify waiting Get()s and pin first connected address
-		close(b.upc)
-		b.downc = make(chan struct{})
-		b.pinAddr = addr.Addr
-		// notify client that a connection is up
-		b.readyOnce.Do(func() { close(b.readyc) })
+	if b.pinAddr != "" {
+		return func(err error) {}
 	}
-
+	// notify waiting Get()s and pin first connected address
+	close(b.upc)
+	b.downc = make(chan struct{})
+	b.pinAddr = addr.Addr
+	// notify client that a connection is up
+	b.readyOnce.Do(func() { close(b.readyc) })
 	return func(err error) {
 		b.mu.Lock()
 		if b.pinAddr == addr.Addr {