"To win this match is important, it's very important to be in the final of Toronto", Nadal said after running his season record to 39-3 in a match which ended after midnight local time.
Federer follows Nadal, with Toronto quarter-finalist Alexander Zverev on third ahead of Juan Martin del Potro, forced to pull out in Canada with a wrist problem. You don't win Masters 1000s very often. "I became involved because of my parents who happen to be tennis coaches, so tennis was part of my life since the very beginning".
Murray hit straight back to level the match after winning the second set 6-1 in convincing style.
"I got nervous, I played a bad game", Nadal said.
"But that's how it is".
"To have the support of all of you the whole week, that's why I'm waking up every morning and trying to go on court practising with the highest passion possible".
Notes: Nadal is fourth in overall titles in the Open era.
However, the 17-time grand slam champion and 32-year-old Spaniard announced his withdrawal just hours after claiming an 80th ATP Tour title.
The World No.1 has been in blistering form all year, and would have been amongst the favourites to win.
The two players broke each other's serve on three occasions in the opening set, which Halep eventually took on a tie-break in the IGA Stadium. She closed out the hard-fought match with her third ace of the day. Nadal said afterwards. "I got a little bit tight and nervous".
"I am sure the tournament will be a success and I wish him and his team all the best". He fought back from a break point again in the eighth and the set went all the way to a tiebreak.
The Briton, playing as a wildcard at an event he won in 2008 and 2011, was way below his best against the 16th seed in the opening set and trailed 4-0 in the opening set after spurning three break points in the fourth game.
A crosscourt backhand saved one and Stephens netted a return on the second.
Tsitsipas had a mini-break in the tie-break but Nadal fought back and took his first match point with a forehand victor. "That I'm capable of doing anything on the court, beating any opponent", he said.