Published: 2019-08-18 01:32:34 BdST
Karim Benzema put Madrid ahead in the 12th minute after a superb piece of wing play from Gareth Bale, who had earned a surprise starting berth due to injury to Eden Hazard after a close-season period of uncertainty over the Welshman's future.
Celta had an equaliser ruled out on the stroke of halftime for offside after a video review but they benefitted from the use of the technology in the 56th minute when Modric was punished for raking his studs against the heel of Denis Suarez.
The hosts could not make the most of the extra man as German midfielder Kroos doubled Madrid's lead five minutes later with an unstoppable strike, while substitute Lucas Vazquez added a third in the 80th after a pass from Benzema.
Celta finally got a goal back in stoppage time when 18-year-old Iker Losada scored two minutes after coming off the bench to make his first-team debut.
The performance was a defiant response from Zinedine Zidane's side after a nightmarish last campaign on all fronts in which the club went through three managers, as well as a poor pre-season campaign which provided two wins from seven games.
"We have to erase everything in the past, we can't be lamenting results that happened before, we start from scratch and with a lot of energy and belief that we can win every competition," Madrid captain Sergio Ramos told reporters.
"This is a very good way to start the campaign, especially after all the speculation during pre-season. We tried not to be affected by all that and just focused on getting in the best form possible and we completely deserved today's result."
Madrid coach Zidane was pleased with the performance and praised his side for keeping control of the game after Modric was sent off.
"We played a very complete game from the start, and we were superb when we had only 10 men," said the Frenchman.
"We had to suffer to get this result and we're very satisfied with it, especially the pre-season we had. We had difficult results but what matters is that we worked hard and the most important thing is how we do in competitive games."