How can I delete a String or avoid adding it after certain condition?

I have a code and it seems to work normally but in minutes I want to start the counter with “0” like this but when it goes from 9 it clears the “0” again.

If I remove the “0” from that line and remove it from the html it works, but it looks really weird without a 0 before it.
minutesTens.innerHTML = “0” + minutes;

What can I improve on this stopwatch, I’m a beginner in javascript.. thanks in advance to everyone.

<div class="contador" id="time">
        <span id="hors">0</span>
        <span class="dots">:</span>
        <span id="minutes">00</span>
        <span class="dots">:</span>
        <span id="seconds">00</span>
        <span class="dots">.</span>
        <span id="tens">00</span>
      </div>
      <div class="btn">
        <button id="btnStart">Start</button>
        <button id="btnPausar">Stop</button>
        <button id="btnResetar">Reset</button>
      </div>

window.onload = function () {
  var tens = 0;
  var seconds = 0;
  var minutes = 0;
  var hors = 0;

  const horsTeans = document.getElementById("hors");
  const minutesTens = document.getElementById("minutes");
  const secondsTens = document.getElementById("tens");
  const secondTens = document.getElementById("seconds");

  const btnStart = this.document.getElementById("btnStart");
  const btnPausar = this.document.getElementById("btnPausar");
  const btnResetar = this.document.getElementById("btnResetar");

  let Intervalo;

  function startTimer() {
    tens++;

    if (tens < 9) {
      seconds.innerHTML = "0" + tens;
    }
    if (tens > 9) {
      secondsTens.innerHTML = tens;
    }
    if (tens > 99) {
      seconds++;
      secondTens.innerHTML = "0" +
        seconds;
      tens = 0;
      secondsTens.innerHTML = "0" + tens;
    }
    if (seconds > 9) {
      secondTens.innerHTML = + seconds;
    }
    if (seconds > 10) {
      seconds = 0;
      minutes += 1;
      minutesTens.innerHTML = "0" + minutes;
    }


    if (minutes > 59) {
      seconds = 0;
      minutes = 0;
      hors++;
      horsTeans.innerHTML = + hors;
    }
  }

  btnStart.onclick = function () {
    clearInterval(Intervalo);
    Intervalo = setInterval(startTimer, 10);
  };

  btnPausar.onclick = function () {
    clearInterval(Intervalo);
  };

  btnResetar.onclick = function () {
    clearInterval(Intervalo);
    tens = "0";
    seconds = "00";
    minutes = "00";
    hors = "00";

    secondsTens.innerHTML = tens;
    secondTens.innerHTML = seconds;
    minutesTens.innerHTML = minutes;
    horsTeans.innerHTML = hors;
  };
};