Australian Robertson was a 4-0 winner over Ali Carter, who was given an emotional reception as he continues his recovery from cancer.
New International champion Walden completed a 4-0 success against Mark Allen, but he appeared to be tired after his return from winning in China last weekend.
That seemed to play out in the evening's group final against 2010 world champion Robertson who just had too much quality in the end.
Walden won the first frame with a 43 and an 87 only for Robertson to level at 1-1 with a 63.
A 134 saw Robertson move 2-1 clear, but Walden won the next two frames including 45 and 61 in the fifth frame.
It was to be the last frame he won as Robertson levelled at 3-3 with a 59 before battling his way to the next three frames to set up a meeting with his rival Judd Trump in the last four on Saturday night.
Defending champion Ronnie O'Sullivan and Ding Junhui contest the first semi-final on Saturday afternoon.
Champion of Champions draw and results
Monday 3rd, Group 4 (first match at 1.00pm)
Ding Junhui (1) 4-2 Dominic Dale
Barry Hawkins (2) 4-1 John Higgins
Group 4 final (7pm)
Ding Junhui (1) 6-5 Barry Hawkins
Tuesday 4th, Group 2 (first match at 1.00pm)
Mark Selby (1) 4-1 Steve Davis
Judd Trump (2) 4-1 Stephen Maguire
Group 2 final (7pm)
Judd Trump 6-1 Mark Selby
Wednesday 5th, Group 1 (first match at 1pm)
Ronnie O'Sullivan (1) 4-2 Stuart Bingham
Shaun Murphy (2) 1-4 Marco Fu
Group 1 final (7pm)
Ronnie O'Sullivan 6-0 Marco Fu
Friday 7th, Group 3 (first match at 1.00pm)
Neil Robertson (1) 4-0 Ali Carter
Ricky Walden (2) 4-0 Mark Allen
Group 3 final
Neil Robertson 6-3 Ricky Walden
Saturday 8th, semi-finals (best of 11 frames)
Ding Junhui v Ronnie O'Sullivan (1pm)
Judd Trump v Neil Robertson (7pm)
Sunday 9th, final (best of 19 frames)
Ding/O'Sullivan v Trump/Robertson