Alexis Sánchez offered an eye-catching 65-minute cameo but Manchester United drew a disappointing crowd of 32, 549 for this second tour outing, against San Jose Earthquakes.

These were the headlines from a game that took four minutes for Sánchez to make an impact. His free-kick was fired in from the left, Eric Bailly found space and a stooping header pinged off JT Marcinkowksi’s bar.

The defender should have scored and United came close seconds later. This time Sánchez strolled through the middle and fed Tahith Chong but the 18-year-old’s back-heel was cleared.

While Sánchez was finally starting his pre-season following a visa issue, Antonio Valencia’s afternoon lasted six minutes, the captain being removed for Matteo Darmian with what looked to be a calf problem.

As Sánchez continued to buzz around, all of this meant a bright start for those inside Levi’s Stadium, home of the San Francisco 49ers.

The problem was the empty seats. A venue that holds up to 75,000 appeared around only a quarter full despite the official number given. This followed the half-filled University of Phoenix Stadium for Thursday’s 1-1 draw with Club America. When United played Real Madrid here last year and Barcelona three years ago the venue was a virtual sell-out.

After Florian Jungwirth clattered Sánchez – drawing a yellow card – Luke Shaw suffered a nutmeg by Nick Lima that led to a free-kick. This yielded nothing as did an Anthony Martial run when he was clear in on Marcinkowski.

Along with Sánchez, James Garner, Chong and Joel Pereira were Jose Mourinho’s other changes from the opening tour match. Garner, another who is 18, made one intervention near his area.At the other end United offered up a sequence of slick interplay that had Sánchez to the fore, alongside Andreas Pereira in midfield who was sharp and tenacious.

Eight minutes before the break United forced a second corner. Pereira swung the ball in from the right, finding Garner’s head, but the youngster could not direct the shot. By the break the Earthquakes had proved feisty opponents, with Sánchez and Pereira being roughed up. The pair were among United’s better players, Sánchez in particular illustrating his class by running the contest via a cocktail of pace and verve.

Lee Grant, Timothy Fosu-Mensah, Axel Tuanazebe, Scott McTominay and Juan Mata were the manager’s changes for the second period as he reshuffled the frontline to have Sanchez playing central, Martial on the left, the Spaniard to the right.

Mikael Stahre changed all of his XI and Mata’s first contribution was to cede possession needlessly to Jackson Yueill in midfield. When United’s No 8 made a diagonal run from his right-hand berth Sánchez found him and Mata, from inside the area, tried to turn the ball back into Martial. He failed but this was a clever United move that will have pleased Mourinho.

So, too, the goal-line clearance an alert Fosu-Mensah made to clear Vako’s shot as United were split open for virtually the first time.

It was Vako who next stood up a free-kick for Yeferson Quintana to beat a clutch of defenders and head at Grant, the keeper making a low save.

When Sánchez went off he was replaced by Mason Greenwood, the 16-year-old operating at centre-forward for United in only a second appearance. On the afternoon’s evidence Sánchez had not suffered from missing the Club América match while waiting for US Immigration to grant his papers for travel.

United were bound to dip with his departure and Grant had to pull off a flying save from a shot from 25 yards by Tommy Thompson, the No1 tipping over the bar. Finally McTominay was offered a gilded chance to claim victory but his close-range header from Greenwood’s cross was disappointing.

Antonio Valencia was forced off after six minutes due to what appeared calf strain.

Mourinho said: “He’s injured. We need to get used to it. Last season he was already in this kind of situation and probably this season we’re going to have more of that.”