JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block">Ближайщие матчи</div>

CSS

body {
  margin: 100px auto;
  width: 300px;
}

.block {
  display: block;
  width: 200px;
  background: grey;
  color: #fff;
  text-align: center;
  position: relative;
}

.block::before {
  content: '';
  position: absolute;
  border: 9px solid transparent;
  border-right: 9px solid grey;
  border-bottom: 9px solid grey;
  left: -18px;
  top: 0;
}