Boothroyd saw at first hand the quality of the west Londoners on Sunday as they went five points clear at the top with a 2-1 win over the Sky Blues.
Adel Taarabt and Wayne Routledge were on target to cancel out Marlon King's opener as Rangers grabbed their first win of 2011.
Having got a recent dip in form out of their systems, Boothroyd feels Rangers remain the team to beat this season.
"I think if anyone finishes above them then they will win it," said Boothroyd.
"It is tight, there are a lot of good teams in and around it and they've been on a bit of a slippery run. But they've got the quality, when games are tight, to go on and win them."
Source: PA
Source: PA