It was a busy enough day for Murray, as he and Lopez first finished off a quarter-final match before coming through a punishing semi-final.
They saw off the British combination of Dan Evans and Ken Skupski before knocking over a grand slam-winning doubles duo in Australian John Peers and Finn Henri Kontinen.
But for Spaniard Lopez it was the most gruelling of days, as he also had a singles semi-final that he won in three tough sets against emerging Canadian talent Felix Auger-Aliassime.
Teaming up with Murray this week has brought the very best out of Lopez, who at the age of 37 has suffered both with injuries and a succession of early defeats at events this year.
Murray said: "It was an unbelievable effort from 'Feli'. He's played a lot of tennis in the [past] couple of days.
"He's not young anymore. He played brilliant, served unbelievably well and I'm really happy to be in the final."
Peers and Kontinen won the Australian Open in 2017 and presented Murray and Lopez with daunting opposition, so the 7-5 6-7 (5-7) 10-7 victory is another step forward, particularly for the Briton, who is returning to action this week from hip surgery.
While Murray is slowly getting his career back on track, Lopez is enjoying his rejuvenation in London.
Asked how he felt physically, Lopez said: "I don't really know — of course I'm tired.
"I've been playing a lot this week, and this year I haven't played much because I was injured at the start of the year so I haven't played two or three matches in a row for six months.
"So my body feels a little bit sore but [I will be] ready for [Monday AEST]."
Murray and Lopez will face veteran American Rajeev Ram and his British partner Joe Salisbury for the title, but Lopez plays singles first, with France's Gilles Simon his opponent in that final.