Jennings' shot looked destined for the top corner just after the restart but Bell threw himself to his left to tip it away.
Both sides produced some excellent passing moves on Saturday, with Motherwell edging possession but a clinical edge was missing.
Motherwell were not helped by a thigh injury to Michael Higdon, which saw Bob McHugh forming a youthful strike partnership with Jamie Murphy.
Kilmarnock manager Kenny Shiels, without a win now 10 games into his reign, signed his son Dean on loan from Doncaster in time to name him among his substitutes.
Danny Buijs was one of five summer signings in the Kilmarnock starting line-up but they quickly found their passing rhythm and pressed Motherwell back.
James Dayton's pace and skill were causing problems and Keith Lasley was perhaps fortunate to survive en early penalty claim when the Kilmarnock wide man went down under his challenge in the box.
However, referee George Salmond decided Dayton had run into his opponent.
Motherwell soon settled and Murphy was inches way from connecting with Nicky Law's low cross after a long spell of possession, built from the back.
The visitors kept the pressure on and Shaun Hutchinson headed just over from one of a series of Stevie Hammell corners.
Darren Randolph beat away Liam Kelly's powerful effort from a tight angle at the other end as both sides continued to string together some impressive passing moves.
Motherwell were enjoying the bulk of possession but Kilmarnock were getting numbers deep to make it difficult to break them down.
The visitors could not find enough space round the outside although a couple of one-twos between Law and Murphy almost got them through the heart of Kilie's defence.
Killie were rarely on the front foot in the first half after their opening flurry but Dayton broke quickly and forced Randolph to dive low to his left to parry his powerful shot on the run.
McHugh had a half-chance in the 44th minute when Murphy broke and slid the ball into the right channel for his strike partner, but Bell pushed the 21-year-old's powerful strike from 18 yards over the bar.
The Scotland international produced a better save seconds after the restart to deny Jennings from 25 yards.
Kelly was soon presented with a chance when Randolph slipped while making a clearance but the midfielder could not keep his first-time effort down as he shot at an empty net from 40 yards.
Murphy was almost through at the other end but he could not take down Tom Hateley's ball over the top.
Kilmarnock made a double switch just before the hour mark when debutant Paul Heffernan and David Silva came on for Gary Harkins and Ben Hutchinson.
Silva soon set up James Fowler with a backheel but the midfielder shot straight at Randolph from 22 yards.
The hosts were enjoying more of the ball in the second half but they were cut open in the 65th minute when Hammell's instant pass set Law clear.
The midfielder had time to get the ball on his favoured right foot and cut inside but he took too long to shoot and Manuel Pascali raced back to make a sliding block.
Chris Humphrey got past Kilmarnock left-back Rory McKeown but shot high and wide from a difficult angle as Motherwell regained the ascendancy without being able to carve a real chance.
However, Stephen Craigan's tackle inadvertently set up Silva to drive from the left, Randolph getting down to hold.
Former Hibernian midfielder Shiels came on for his debut and Kilmarnock enjoyed a late rally as Motherwell appeared to tire - but Randolph was untroubled.