CARSON: Landon Donovan embraced his wife and cradled his young son for the first time after a soccer game, basking in the moment he craved when he ended his 21-month MLS retirement.

Donovan then handed off his son and ran straight to the LA Galaxy's locker room to get on a treadmill.

The most accomplished player in US history truly realised the length of the challenge stretching before him after he returned to the Galaxy as a second-half substitute Sunday night, playing about 10 minutes in their dominant 4-2 victory over Orlando City.

"I'm so far away," the 34-year-old Donovan said. "I came into a game where both teams were exhausted, and I was the slowest player on the field. I need to get myself ready to compete in a real way. Bruce and the coaching staff need to know what when they put me in, it can mean something. So tonight worked out well, but I need to be able to contribute."

Donovan, the top scorer in the history of MLS and the U.S. men's national team, announced his comeback with the Galaxy three days earlier. He has committed to return for at least the rest of this season, which he hopes will end with his record seventh MLS Cup championship.

Wearing a No. 26 jersey instead of his usual No. 10, he got a lengthy standing ovation from the StubHub Center crowd before entering in the 83rd minute of his first game since the 2014 MLS Cup final.

"I was excited, but it's just weird to be back in this role, because it's real," Donovan said. "It's really intense. The league, I think, has gotten dramatically better since I've been gone. When I looked at Orlando's lineup, they have really, really good players all over the field. It's just amazing to see how this league has changed. There's no room to be not fit, not sharp. I'm got to be on it if I want to contribute."

His teammates were in fine form: Giovani Dos Santos scored two goals and Alan Gordon added another during a first-half barrage for the Galaxy (11-4-14), who took sole possessions second place in the Western Conference with their second straight win. Captain Robbie Keane also scored as a second-half substitute while LA extended its unbeaten streak to five matches.

The Galaxy's bulging lead was the only reason Donovan got to play in his first game back.

"It's going to take a while," Galaxy coach Bruce Arena said. "We knew that. Probably no other circumstances would have allowed me to play him today, but I wanted him to get out there and reward the crowd for showing up and all, and it helps Landon see how far he has to go."

The Galaxy supporters began to sing for Donovan in the 70th minute after Keane's goal. When he took off his warmup shirt to don the No. 26 jersey, Donovan got another ovation that grew to a crescendo when he checked in.

Donovan hadn't been training extensively before deciding to return, and his fitness was barely enough for a late-game run along the left side of the Galaxy's formation.

"I think I had much more impact today in the locker room and helping out a few guys at halftime than I did on the field," Donovan said. "If that's the way I contribute, that's great."

Dos Santos, the Mexican star now wearing Donovan's No. 10, scored or assisted on every goal in a monster performance for the Galaxy, who have struggled to get their entire star-stacked lineup healthy in a season characterized largely by frustration despite their lofty place in the standings.

The Galaxy hope they're near the end of the injury troubles that partly inspired Donovan's comeback. Keane and Van Damme returned to action after breaks, but Gerrard is still out — and Gyasi Zardes will be sidelined until the postseason.

Donovan doesn't know what role he'll play in the final five games of the regular season, but he is eager to build on this tentative restart.

"I might have played five minutes or so, maybe completed one pass, and it really makes you realize that it's a whole different level," Donovan said. "I've got to get myself going again so I can really contribute, because not every week is going to be a charity five or 10 minutes."