The Liverpool captain and his England team-mate were impressive in Jurgen Klopp’s midfield as the hosts outperformed the Red Devils in the first leg at Anfield last Thursday.
Daniel Sturridge made the breakthrough from the penalty spot before Roberto Firmino added a second with 16 minutes remaining of the last-16 clash on Merseyside.
The Liverpool manager appears to have given his Reds squad a break ahead of their return leg against Louis van Gaal’s struggling side.
Henderson, who named as Steven Gerrard’s successor as captain at the end of the 2014/15 season, posted a photo of a golf course as he prepared for 18 holes with Lallana.
Henderson wrote on his Instagram page: “⛳️ ☀️ @officiallallana”
Liverpool are in seventh place in the Premier League table.
MORE: Latest Man Utd news
MORE: Latest Arsenal news
MORE: The latest football news