Olivier Giroud scored twice as Chelsea beat St Patrick's 4-0 to seal Frank Lampard's first win in charge of the club.
Giroud came off the bench to net a second-half double in Dublin after first-half goals from Mason Mount and Emerson Palmieri had put the visitors in control.
Despite making 11 changes at half-time, Lampard - in just his second match as Chelsea boss following their midweek draw at Bohemians - will still have taken much from the friendly at Richmond Park as he gears up for the start of the new Premier League season next month.
Mount, who spent the previous campaign playing under Lampard while on loan at Derby, was handed a first start as the new manager fielded a strong-looking lineup, with the midfielder catching the eye with a neatly-taken opening goal after 14 minutes.
Lampard also began with a front two of Tammy Abraham and Michy Batshuayi, two other players recalled after being loaned out last season.
The Belgian forward impressed with a dynamic first-half display in which he was unlucky not to score, before Lampard changed both personnel and shape to a 4-2-3-1 in the second period, with the experienced Giroud leading the line.
And Giroud staked a claim to start away to Manchester United on the opening weekend of the season with two well-taken goals to complement a first clean sheet under the new manager.
"Good performance, good result," Lampard told Sky Sports.
"We could have scored a lot more goals was the one thing I was slightly frustrated with. But I was particularly impressed with the energy of the team I the first half, which I was thought was great.
"You have to put everything into these games to get something out of them. And the second half, I did not quite like as much and those are the things that show you need to keep working.
"Fitness is what we are striving for and combinations and we already have combinations with the ball, but our fitness can get much netter.
"A lot has been made of the younger players we have here and they need to know that if they impress and put what they did into a game like today's, then great.
"From the first moments you could see that Mason, Tammy and Tomori were really at it and that is what we want. We need to have competition in the squad, we work hard here, the academy has been first class for years and we want those players to show they deserve a place in the team."