England began their title defence with a 33-12 win over Ireland in front of a record Women's Six Nations crowd.
Hooker Amy Cokayne's try and two scores from prop Sarah Bern gave world champions England a 21-0 half-time lead in front of the 77,120 crowd.
Early in the second half, Jess Breach scored her record 54th try to seal the bonus point, before Ireland got on the scoreboard after an hour when replacement Anna McGann swivelled over under pressure.
Ellie Kildunne added a fifth try for the Red Roses in the final quarter of an hour as she shrugged off a couple of challenges and charged over, before Ireland captain Erin King went over under the posts in consolation.
England, who are on a record 34-game winning run, are seeking their fifth Six Nations Grand Slam in a row and eighth consecutive title.
France are top of the Women's Six Nations table due to their superior points difference over England after they beat Italy 40-7 at the Stade des Alpes earlier on Saturday.
France are expected to be England's closest challengers, with the two favourites set to meet on the final weekend on May 17.
Scotland held off a resurgent Wales to win 24-19 at the Principality Stadium in the last match of the opening day.
England captain and Player of the Match Meg Jones speaking to the BBC:
"There were always going to be nerves. We are going into a big campaign off the back of an amazing World Cup.
"To have this crowd is phenomenal. We wanted to play with big crowds.
"We found ways [to win]. We dominated that set-piece and had the luck of the bounce sometimes.
"Definitely some nerves but we will freshen up on that. Really proud of the girls. We all dug in to get the victory."
Ireland head coach Scott Bemand speaking to the BBC:
"That's a very good Red Roses team - world champions, current No 1 in the world. Typically they go through the gears and blow teams away at the end.
"I'm really pleased the second half was 12-12. I'm really encouraged by the spirit the Irish girls showed.
"There are elements of the first half where we gave it away too early in the attack threat. We have to learn to go deeper in the attack threats.
"I thought we were a bit hard done by. I thought we had a good turnover in our 22 but the penalty was given against us and they got their first try off the back of it.
"At some point, people will realise we have some firepower and we create turnovers. And with two even teams out there eventually you get a bit more of the rub of the green."
England's next travel to face Scotland at Murrayfield for round two on April 18 with a 1.30pm kick-off.
Ireland host Italy at the Dexcom Stadium in Galway for their round-two clash on the same day with a 5.40pm kick-off.
Scotland saw off a late Wales fightback to take a 24-19 victory at the Principality Stadium in Cardiff as they began a new era under Sione Fukofuka.
Wales led 12-10 at half-time but tries from Shona Campbell and Lucia Scott moved Scotland ahead with 15 minutes to go.
However, Wales captain Kate Williams got her side back into the game to set up a thrilling end to the match. Buoyed by the crowd, Wales dug deep but had to settle for a bonus losing point, as they lost by less than seven points.
Scotland will host England at Murrayfield next Saturday while Wales face France.
