Despite scoring twice in a frantic five-minute period at the start of the second half, United ended the first Asia Tour match on level terms with Urawa Red Diamonds in Tokyo's Saitama Stadium.
Inspired by goals from Darren Fletcher and Cristiano Ronaldo, the Reds overturned a 1-0 half-time deficit to take the lead on 52 minutes. But drizzly conditions and a late equaliser from home crowd favourite Shinji Ono put a dampener on proceedings.
Despite the rain, both sides were determined to keep the ball on the ground and Paul Scholes was particularly effective early on, orchestrating United's attacks from the centre of midfield. Cristiano Ronaldo didn't disappoint his admirers either, pulling out his party tricks as early as the second minute.
The Portuguese winger, who drew cheers with every touch, forced Urawa Reds goalkeeper Tsukuki into his first save on 25 minutes when he shot fiercely towards the near post.
But a minute later, the Premier League champions were behind. Urawa's Hideki Uchidate found space in the United half and let fly from 30 yards with a shot that swerved wickedly past Edwin van der Sar. In fact, the deviation was so severe, van der Sar was left diving in the wrong direction.
Urawa threatened again four minutes later but then seemed content to settle on the ball. So it was left to Wayne Rooney to inject a little sparkle into the match. With 43 minutes on the clock, Rooney provided an inch-perfect cross for Paul Scholes, but the midfielder could only steer his header into the arms of a grateful Tsukuki.
A minute later, the England striker had everyone at the Saitama Stadium on their feet after coming within a whisker of a spectacular equaliser. Rooney picked up the ball inside the United half before turning on the speed to brush aside what seemed like most of the Urawa defence. But, when left with only Tsukuki to beat, the Reds' no.8 scuffed his shot and the goalkeeper stretched out a right boot to divert it around the post.
Sir Alex made three changes at the interval, bringing on defenders Danny Simpson, Johnny Evans and Mikael Silvestre for Nemanja Vidic, Rio Ferdinand and Patrice Evra. Perhaps it should have been the home side shoring up the defence. It wasn't, and within seven minutes of the restart, United were 2-1 up.
Darren Fletcher scored the equaliser from 12 yards after substitute goalkeeper Yamagishi failed to hold a Michael Carrick shot moments earlier. Then, in the 52nd minute, the crowd got what they came for when Cristiano Ronaldo cut inside from the left wing to unleash a rasping drive past Yamagishi at the near post. It was typical of so many of Ronaldo's goals last season and a reminder of how dangerous the Portuguese winger can be when given space.
United looked comfortable thereafter but failed to capitalise on a number of half chances. Shinji Ono, however, was lethal when presented an opportunity in the 78th minute. The midfielder showed enormous composure to turn Johnny Evans and roll the ball coolly past Edwin van der Sar and into the far corner.
It was the last significant piece of action in an entertaining and free-flowing affair. The Reds now travel to South Korea for Friday's match against FC Seoul (kick-off 12:00 BST).
United: Van der Sar, Brown, Ferdinand (Evans, 45), Vidic (Simpson, 45), Evra (Silvestre, 45), Ronaldo, Fletcher, Carrick (O'Shea, 69), Giggs (Smith, 69), Scholes, Rooney
Subs: Kuszczak, Heaton, Bardsley
Urawa Red Diamonds: Tsukuki (Yamagishi, 45), Hosogai, Horinouchi, Nene, Yamada, Uchidate (Hiriwaka, 45), Hasebe, Soma (Okano, 91), Ono, Ponte (Koike, 83), Tanaka (Nagai, 75)
Subs: Tsutsumi, Sakai, Nishizawa