Set item on v-select through a button press -> @change is not triggered

I have a button

<v-btn
  v-if="getEnviroment"
  @click="fillOther"
>
  fillOther
</v-btn>

on the page visible only for local host. A click on this button should select the first element of the v-select.

Setting the item is simple:

fillOther () {
  this.inputForm.tsi = 69
}

The issue is, that the @change Event is not triggered through this.

How can i tigger the @change event on the v-select?

<v-select
  id="TsiAuswahl"
  v-model.trim="inputForm.tsi"
  :items="tsiItems"
  label="Leistungsart"
  item-text="anzeigetext"
  item-value="wert"
  data-test="tsi"
  :return-object="false"
  @change="onChangeTSI"
>
  <template
    v-slot:item="{item }"
  >
    <span :id="'tsiSelect_listItem_' + item.id">{{ item.anzeigetext }}</span>
  </template>
</v-select>

Thank you in advance!