Robin van Persie and Radamel Falcao both scored while on international duty on Friday to give Manchester United manager Louis van Gaal food for thought ahead of the resumption of the season.
Van Persie netted Netherlands' third goal in their 3-1 win over Kazakhstan in Amsterdam, scoring a 89th minute penalty as Guus Hiddink's side returned to winning ways in European Championship qualifying.
Meanwhile, Falcao marked his first start for Colombia in 11 months with the opening goal in the 3-0 win over El Salvador to become the nation's second all-time leading goalscorer.
Rising highest from a Santiago Arias cross after just seven minutes, Falcao scored his second goal of the season after opening his account for the campaign in Manchester United's 2-1 win over Everton.
Despite beginning with Falcao and Van Persie in the Manchester United first team, alongside captain Wayne Rooney, there is a growing view that van Gaal may only be able to start with two in attack, particularly during the club's difficult away games.
Rooney's role as captain makes his position all but cemented, while record signing Angel di Maria has been ever-present since joining from Real Madrid in August.
Van Gaal may soon have to choose between Van Persie and Falcao, both of whom have struggled from a string of injury problems in the last year.
Falcao missed the end of last season and the World Cup finals due to an anterior cruciate knee ligament injury. It delayed his return to action in August, prior to joining Manchester United on a season-long loan deal from Monaco.
Van Persie has suffered from groin, toe and knee problems throughout 2014, injury issues which have drawn questions over his long-term United future.
However, speaking last month following the 5-3 defeat to Leicester City, van Gaal threw Rooney's continued role as a striker into doubt by criticising his performance as the spearhead of the United attack.
"We have played well, but can improve, and I was not so satisfied with Rooney as a striker and Mata as midfielder," Van Gaal said.
"That is why I changed. Rooney can play in more positions, he's a multi-functional player and I have tried him in a striker's position. He has played well, but not spectacular. Falcao is a striker and I think he can do it better."